Inhibitors of arginase and their therapeutic applications

ABSTRACT

Compounds according to Formula I and Formula II are potent inhibitors of Arginase I and II activity: 
                         
where R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , D, M, X, and Y are defined as set forth in the specification. The invention also provides pharmaceutical compositions of the compounds and methods of their use for treating or preventing a disease or a condition associated with arginase activity.

The present application is a continuation of U.S. patent applicationSer. No. 13/090,714, filed on Apr. 20, 2011, and it claims the benefitof priority of U.S. Provisional Applications No. 61/326,892, which wasfiled on Apr. 22, 2010, and No. 61/413,202, which was filed on Nov. 12,2010, the entire disclosures of which are incorporated by reference asif fully set forth herein.

BACKGROUND OF THE INVENTION

The present invention relates generally to inhibitors of arginase andtheir use for the treatment of pathological states. Two isoforms ofarginase have been identified to date. arginase I (ARG I), that isexpressed in the cytosole and arginase II (ARG II), that is expressed inmitochondria. The arginase enzymes together with the nitric oxidesynthase (NOS) enzymes play an important role in regulating the levelsof nitric oxide in cells and in the development of pathophysiologicaldisease states.

The arginases are implicated in various pathological states. Theseinclude without limitation erectile dysfunction, pulmonary hypertension,hypertension, atherosclerosis, renal disease, asthma, T-celldysfunction, ischemia reperfusion injury, neurodegenerative diseases,wound healing, and fibrotic diseases. Although the mechanism of actionof arginase enzymes in these disease states is still a subject ofongoing research, several studies imply that the arginase enzymes areoften upregulated during pathological disease states.

For example, it is postulated that upregulation of arginase activityresults in reduced levels of arginine which in turn reduces the level ofnitric oxide (NO) a physiologically important signaling molecule that isrequired for cell division, arterial vasodilation, regulation of bloodflow and for controlling muscular and neurological signal transduction.

In addition to its role in regulating nitric oxide (NO) levels, arginasealso affects production of critical polyamines such as putrescine,spermidine and spermine. As arginase catabolizes L-arginine it producesornithine. Ornithine is subsequently converted to putrescine, spermidineand spermine via ornithine decarboxylase, spermidine synthase andspermine synthase respectively. Thus, the arginase enzymes controlphysiological signaling events by controlling the intracellular levelsof polyamine signal transducers. See Wang, J-Y; and Casero, Jr., R. A.,Ed; Humana Press, Totowa, N.J., 2006. Ornithine also provides analternative biosynthetic pathway to proline and thereby supportscollagen production (Smith, R. J.; Phang, J. M., The importance ofornithine as a precursor for proline in mammalian cells. J. Cell.Physiol. 1979, 98, 475-482. Albina, J. E.; Abate, J. A.;Mastrofrancesco, B. Role of ornithine as a proline precursor in healingwounds. J. Surg. Res. 1993, 55, 97-102.)

Given the role of arginase in various pathological states, the presentinvention provides Formula I and Formula II compounds as inhibitors ofarginase activity, as well as methodologies for using the inventivecompounds as therapeutics.

SUMMARY OF THE INVENTION

The present invention provides certain boron-containing compoundsaccording to Formulae I and II as described herein that are inhibitorsof arginase activity. The invention also provides methods for using theinventive compounds in treatment. In one embodiment, therefore,inventive compounds and their pharmaceutically acceptable formulationsare provided as therapeutic agents capable of inhibiting arginaseactivity. Compounds and pharmaceutical formulations in accordance withthis invention are useful for treating a number of diseases andconditions, including but not limited to pulmonary hypertension,erectile dysfunction (ED), hypertension, atherosclerosis, renal disease,asthma, T-cell dysfunction, ischemia reperfusion injury,neurodegenerative diseases, wound healing, and fibrotic diseases.

In one embodiment, the present invention provides compounds that conformto Formula I and to stereoisomers, tautomers, prodrugs, andpharmaceutically acceptable salts or esters thereof:

In Formula I, R¹ is selected from the group consisting of —OH, OR^(a),and NR^(b)R^(c). Substituent R^(a) is selected from the group consistingof hydrogen, straight or branched chain (C₁-C₆)alkyl, (C₃-C₁₄)aryl,(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene-,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene-, and (C₃-C₁₄)aryl(C₁-C₆)alkylene-.Substituents R^(b) and R^(c) are each independently selected from thegroup consisting of H, —OH, straight or branched (C₁-C₆)alkyl,—S(O)₂—(C₁-C₆)alkyl, (C₃-C₁₄)aryl-S(O)₂—,(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene-, and(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene-.

Substituent R² in Formula I is selected from the group consisting ofstraight or branched (C₁-C₆)alkyl, straight or branched (C₂-C₆)alkenyl,straight or branched (C₂-C₆)alkynyl, (C₃-C₁₄)aryl, (C₃-C₁₄)-cycloalkyl,(C₃-C₁₄)aryl(C₁-C₆)alkylene-, (C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene-,(C₃-C₁₄)heteroaryl, (C₃-C₁₄)heterocycloalkyl,(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene-,(C₃-C₁₄)heteroaryl-(C₃-C₆)heterocycloalkylene-,(C₃-C₁₄)aryl-(C₃-C₁₄)heterocycloalkylene-,(C₃-C₁₄)-aryl-(C₁-C₆)alkyl-(C₃-C₁₄)heterocycloalkylene-,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkyl-(C₃-C₁₄)heterocycloalkylene-,(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkyl-(C₃-C₁₄)heterocycloalkylene-, and—(CH₂)_(m)—(X)_(u)—(CH₂)_(n)—(Y)_(v)—R^(f).

When R² is —(CH₂)_(m)—(X)_(n)—(CH₂)_(n)—(Y)_(v)—R^(f), u and v are eachindependently 0 or 1 such that u+v≥1. Subscripts m and n are eachindependently 0, 1, 2, 3, 4, 5, or 6, wherein m+n≥1.

Variables X and Y are independently selected from the group consistingof —NH—, —O— and —S-Substituent R^(f) is selected from the groupconsisting of H, hydroxyl, straight or branched (C₁-C₆)alkyl and(C₃-C₁₄)aryl.

Substituents R³ and R⁴ are each independently hydrogen or straight orbranched (C₁-C₆)alkyl.

Alternatively, R³ and R⁴ together with the boron atom to which they arebound form a 5- or 6-membered ring that is fully or partially saturated,and that optionally contains 1-3 additional heteroatom ring membersselected from O, S, and N.

Also contemplated are compounds wherein the boronic acid moiety inFormula I is esterified with a sugar. Compounds of this class are usefulas prodrugs.

Substituent R⁵ is selected from the group consisting of H, straight orbranched (C₁-C₆) alkyl, and (C₁-C₆)alkyl-C(O)—.

In formula I, D is selected from the group consisting of straight orbranched (C₁-C₆)alkylene, straight or branched (C₂-C₈)alkenylene,(C₃-C₁₄)arylene, straight or branched (C₂-C₈)alkynylene, and(C₃-C₁₄)cycloalkylene. In some embodiments, one or more —CH₂— groups inD are optionally and independently replaced with a moiety selected fromgroup the consisting of —O—, —NR′—, —S—, —SO—, —SO₂—, and —CR′R″—wherein R′ and R″ are each independently selected from the groupconsisting of H, (C₁-C₈)alkyl, and (C₃-C₆)aryl. In other embodiments,any two adjacent —CH₂— groups optionally represent two members of a(C₃-C₁₄)-cycloalkylenyl group.

Any alkyl, alkylene, alkenyl, alkenylene, alkynyl, or alkynylene inFormula I is optionally substituted with one or more members selectedfrom the group consisting of halogen, oxo, —COOH, —CN, —NO₂, —OH,—NR^(d)R^(e), —NR^(g)S(O)₂R^(h), (C₁-C₆)alkoxy, and (C₃-C₁₄)aryloxy.

Substituents R^(d), R^(e), R^(g), and R^(h) are independently selectedfrom the group consisting of H, straight or branched (C₁-C₆)alkyl,optionally substituted (C₃-C₁₄)aryl(C₁-C₆)alkylene-, (C₁-C₆)alkoxy,optionally substituted (C₃-C₁₄)aryl, (C₁-C₆)hydroxyalkyl,(C₁-C₆)aminoalkyl, H₂N(C₁-C₆)alkylene-, optionally substituted(C₃-C₆)cycloalkyl, optionally substituted (C₃-C₁₄)heterocycloalkyl,optionally substituted (C₃-C₁₄)heteroaryl, optionally substituted(C₃-C₁₄)aryl-(C₁-C₆)alkylene-, NR′R″C(O)—, and(C₃-C₆)aryl-(C₃-C₁₄)-cycloalkylene-, and R′ and R″ can eachindependently be selected from the group consisting of H, (C₁-C₈)alkyl,and (C₃-C₆)aryl.

Any aryl, heteroaryl, cycloalkyl, or heterocycloalkyl is optionallysubstituted with one or more members selected from the group consistingof halogen, —OH, oxo, —COOH, (C₃-C₁₄)aryl(C₁-C₆)alkylene-, —CN, —NO₂,—NH₂, (C₁-C₆)alkyl-S—, (C₃-C₁₄)cycloalkyl, (C₃-C₁₄)heterocycloalkyl,(C₃-C₁₄)aryl, (C₃-C₁₄)heteroaryl, —C(O)NH—(C₁-C₆)alkyl,—NHC(O)—(C₁-C₆)alkyl, (C₁-C₆)alkyl, (C₂-C₈)alkenyl, (C₂-C₈)alkynyl,(C₁-C₆)alkoxy, (C₁-C₆)haloalkyl, and (C₁-C₆)hydroxyalkyl.

It should be understood that, notwithstanding the description of FormulaI given herein, Formula I does not include2-amino-4-borono-2-methylbutanoic acid.

The present invention also provides compounds that conform to FormulaII, to stereoisomers, tautomers, prodrugs, and pharmaceuticallyacceptable salts or esters thereof, and to their pharmaceuticallyacceptable formulations as therapeutics for treating various diseasestates associated with an imbalance of the arginase enzymes.

In Formula II, R⁶ is selected from the group consisting of OR^(a), andNR^(b)R^(c).

Substituent R^(a) is selected from the group consisting of hydrogen,straight or branched chain (C₁-C₆)alkyl, (C₃-C₈)cycloalkyl,(C₃-C₁₄)aryl, (C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene-,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene-, and (C₃-C₁₄)aryl(C₁-C₆)alkylene-,while substituent groups R^(b) and R^(c) are each independently selectedfrom the group consisting of H, —OH, straight or branched (C₁-C₆)alkyl,—S(O)₂—(C₁-C₆)alkyl, (C₃-C₁₄)aryl-S(O)₂—,(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene-, and(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene-.

Substituent R⁷ is selected from the group consisting of H, straight orbranched (C₁-C₆) alkyl, (C₃-C₁₄)aryl(C₁-C₆)alkylene-,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene-,(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene- and (C₁-C₆)alkyl-C(O)—.

Variable X in Formula II is selected from the group consisting of a(C₃-C₁₄)-cycloalkylene and (C₃-C₁₄)heterocycloalkylene and variable M isselected from the group consisting of a bond, (C₁-C₆)alkylene-, —O—,—C(O)—, —C(S)—, —C(O)NH—, —C(S)NH—, —S—, —S(O)—, —S(O)₂—, —NR′—, and—C═NR¹¹—.

Variable Y in Formula II is selected from the group consisting of H,(C₁-C₁₄)alkyl, —NR′R″, hydroxy(C₁-C₆)alkylene, (C₃-C₁₄)-cycloalkyl,(C₃-C₁₄)-cycloalkyl-(C₁-C₆)alkylene, (C₃-C₁₄)aryl,(C₃-C₁₄)aryl-(C₁-C₆)alkylene, (C₃-C₁₄)heterocycloalkyl,(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene, (C₃-C₁₄)heteroaryl,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene,(C₃-C₁₄)heteroaryl-(C₃-C₆)heterocycloalkylene-,(C₃-C₁₄)aryl-(C₃-C₁₄)heterocycloalkylene-,(C₃-C₁₄)-aryl-(C₁-C₆)alkyl-(C₃-C₁₄)heterocycloalkylene-,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkyl-(C₃-C₁₄)heterocycloalkylene-, and(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkyl-(C₃-C₁₄) heterocycloalkylene-.

In one embodiment X is a (C₃-C₁₄)-cycloalkylene, M is a bond and Y is—NH₂. In other aspects of the present invention, X is a(C₃-C₁₄)heterocycloalkylene and Y is selected from the group consistingof (C₃-C₁₄)-cycloalkyl, (C₃-C₁₄)aryl, (C₃-C₁₄)aryl-(C₁-C₆)alkylene,(C₃-C₁₄)heteroaryl and (C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene. For example,Y can be a (C₃-C₁₄)heteroaryl, a (C₃-C₁₄)aryl, a (C₃-C₁₄)cycloalkyl, ora (C₃-C₁₄)aryl-(C₁-C₆)alkylene.

Substituent groups R⁸ and R⁹ are independently selected from hydrogen,straight or branched (C₁-C₆)alkyl, (C₃-C₈)cycloalkyl, (C₃-C₁₄)aryl, andC(O)—R′. Alternatively, R⁸ and R⁹ together with the boron atom to whichthey are bound form a 5- or 6-membered ring that is fully or partiallysaturated, and that optionally contains 1-3 additional heteroatom ringmembers selected from O, S, and N. In an embodiment of the invention, R⁸and R⁹ together with the boron atom to which they are bound are linkedto form a 5-membered dioxaborolane or a 6-membered dioxaborinane ringwhich is optionally fused with a cycloalkyl, heterocyclic or aromaticring.

In Formula II, D is selected from the group consisting of straight orbranched (C₃-C₅)alkylene, straight or branched (C₂-C₈)alkenylene,straight or branched (C₂-C₈)alkynylene, (C₃-C₁₄)arylene, and(C₃-C₁₄)cycloalkylene. In one embodiment one or more —CH₂— groups in Dare optionally and independently replaced with a moiety selected fromthe group consisting of O, NR′, S, SO, SO₂, and CR′R″. No two adjacent—CH₂— groups in D, however, are simultaneously O, NR′, S, SO, or SO₂.

For certain Formula II compounds, any two adjacent —CH₂— groups in Doptionally represent two members of a (C₃-C₁₄)-cycloalkylenyl group. Inother embodiments, D conforms to one of formulae -L¹-L²-CH₂—CH₂—,—CH₂-L¹-L²-CH₂—, —CH₂—CH₂-L¹-L²-, -L¹-CH₂—CH₂-L²-, -L¹-CH₂-L²-CH₂—, or—CH₂-L¹-CH₂-L²-. The variables L¹ and L² are independently selected fromthe group consisting of O, NR′, S, SO, SO₂, and CR′R″, wherein R′ and R″are as defined below. In embodiments where -L¹ and -L² are adjacent toeach other, however, L¹ and L² are not simultaneously O, NR′, S, SO or aSO₂ group.

Substituents R′ and R″ in Formula II are independently selected from thegroup consisting of H, (C₁-C₈)alkyl, —C(O)—(C₁-C₈)alkylene, optionallysubstituted (C₃-C₆)aryl, optionally substituted(C₃-C₁₄)aryl(C₁-C₆)alkylene-, optionally substituted (C₁-C₆)aminoalkyl,optionally substituted (C₃-C₆)cycloalkyl, optionally substituted(C₃-C₁₄)heterocycloalkyl, optionally substituted (C₃-C₁₄)heteroaryl.

Moreover, any alkyl, alkylene, aryl, heteroaryl, cycloalkyl, orheterocycloalkyl substituent as defined herein is optionally substitutedwith one or more members selected from the group consisting of halogen,oxo, —COOH, —CN, —NO₂, —OH, —NR^(d)R^(e), —NR^(g)S(O)₂R^(h),(C₁-C₆)alkyl, (C₁-C₆)haloalkyl, (C₁-C₆)haloalkoxy, (C₁-C₆)alkoxy,(C₃-C₁₄)aryl, (C₃-C₁₄)heteroaryl, (C₃-C₁₄)heterocycloalkyl,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene and (C₃-C₁₄)aryloxy.

Each of R^(d), R^(e), R^(g), and R^(h) are independently selected fromthe group consisting of H, straight or branched (C₁-C₆)alkyl, optionallysubstituted (C₃-C₁₄)aryl(C₁-C₆)alkylene-, optionally substituted(C₃-C₁₄)aryl, (C₁-C₆)hydroxyalkyl, (C₁-C₆)aminoalkyl,H₂N(C₁-C₆)alkylene-, optionally substituted (C₃-C₆)cycloalkyl,optionally substituted (C₃-C₁₄)heterocycloalkyl, optionally substituted(C₃-C₁₄)heteroaryl, optionally substituted (C₃-C₁₄)aryl-(C₁-C₆)alkylene-and NR′R″C(O)—.

The present invention also provides a pharmaceutically acceptable salt,stereoisomer, tautomer, or prodrug of Formula II compounds.

Compounds in accordance with Formula I or II and their pharmaceuticalformulations are useful for treating a number of diseases andconditions, including but not limited to pulmonary hypertension,erectile dysfunction (ED), hypertension, atherosclerosis, renal disease,asthma, T-cell dysfunction, ischemia reperfusion injury,neurodegenerative diseases, wound healing, and fibrotic diseases.

In one embodiment, the present invention provides a pharmaceuticalcomposition that comprises a therapeutically effective amount of atleast one of the compounds of Formula I or Formula II, and apharmaceutically acceptable carrier.

The invention provides in one embodiment a method for inhibitingarginase I, arginase II, or a combination thereof in a cell comprisingcontacting the cell with at least one compound according to Formula I orFormula II. Pursuant to another embodiment, the invention provides amethod for treating or preventing a disease or a condition associatedwith expression or activity of arginase I, arginase II, or a combinationthereof in a subject, comprising administering to the subject atherapeutically effective amount of at least one compound of Formula Ior Formula II.

Pursuant to one embodiment, as noted above, the invention provides acompound of Formula I or Formula II for the treatment or prevention of adisease or condition associated with expression or activity of arginaseI, arginase II, or a combination thereof in a subject. The inventionalso provides, in another embodiment, the use of a compound of Formula Ior Formula II for the same purpose. Alternatively, another embodimentprovides for the use of Formula I or Formula II compounds in themanufacture of a medicament for treatment or prevention of a disease orcondition associated with expression or activity of arginase I, arginaseII, or a combination of both enzymes in cells.

DETAILED DESCRIPTION

The compounds as described herein are small molecule inhibitors ofarginase that conform to Formula I or II. As will be apparent from thedescription hereinbelow, some Formula II compounds also are Formula Icompounds. The compounds and their pharmaceutical compositions areuseful in treating or preventing diseases or conditions that areassociated with the expression or activity of arginase.

Definitions

“Alkyl” refers to straight, branched chain, or cyclic hydrocarbyl groupsincluding from 1 to about 20 carbon atoms. For instance, an alkyl canhave from 1 to 10 carbon atoms or 1 to 5 carbon atoms. Exemplary alkylincludes straight chain alkyl groups such as methyl, ethyl, propyl,butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, andthe like, and also includes branched chain isomers of straight chainalkyl groups, for example without limitation, —CH(CH₃)₂,—CH(CH₃)(CH₂CH₃), —CH(CH₂CH₃)₂, —C(CH₃)₃, —C(CH₂CH₃)₃, —CH₂CH(CH₃)₂,—CH₂CH(CH₃)(CH₂CH₃), —CH₂CH(CH₂CH₃)₂, —CH₂C(CH₃)₃, —CH₂C(CH₂CH₃)₃,—CH(CH₃)CH(CH₃)(CH₂CH₃), —CH₂CH₂CH(CH₃)₂, —CH₂CH₂CH(CH₃)(CH₂CH₃),—CH₂CH₂CH(CH₂CH₃)₂, —CH₂CH₂C(CH₃)₃, —CH₂CH₂C(CH₂CH₃)₃,—CH(CH₃)CH₂CH(CH₃)₂, —CH(CH₃)CH(CH₃)CH(CH₃)₂, and the like. Thus, alkylgroups include primary alkyl groups, secondary alkyl groups, andtertiary alkyl groups.

The phrase “substituted alkyl” refers to alkyl substituted at 1 or more,e.g., 1, 2, 3, 4, 5, or even 6 positions, which substituents areattached at any available atom to produce a stable compound, withsubstitution as described herein. “Optionally substituted alkyl” refersto alkyl or substituted alkyl.

Each of the terms “halogen,” “halide,” and “halo” refers to —F, —Cl,—Br, or —I.

The terms “alkylene” and “substituted alkylene” refer to divalent alkyland divalent substituted alkyl, respectively. Examples of alkyleneinclude without limitation, ethylene (—CH₂—CH₂—). “Optionallysubstituted alkylene” refers to alkylene or substituted alkylene.

“Alkene” refers to straight, branched chain, or cyclic hydrocarbylgroups including from 2 to about 20 carbon atoms having one or morecarbon to carbon double bonds, such as 1 to 3, 1 to 2, or at least onecarbon to carbon double bond. “Substituted alkene” refers to alkenesubstituted at 1 or more, e.g., 1, 2, 3, 4, 5, or even 6 positions,which substituents are attached at any available atom to produce astable compound, with substitution as described herein. “Optionallysubstituted alkene” refers to alkene or substituted alkene.

The term “alkenylene” refers to divalent alkene. Examples of alkenyleneinclude without limitation, ethenylene (—CH═CH—) and all stereoisomericand conformational isomeric forms thereof. “Substituted alkenylene”refers to divalent substituted alkene. “Optionally substitutedalkenylene” refers to alkenylene or substituted alkenylene.

“Alkyne or “alkynyl” refers to a straight or branched chain unsaturatedhydrocarbon having the indicated number of carbon atoms and at least onetriple bond. Examples of a (C₂-C₈)alkynyl group include, but are notlimited to, acetylene, propyne, 1-butyne, 2-butyne, 1-pentyne,2-pentyne, 1-hexyne, 2-hexyne, 3-hexyne, 1-heptyne, 2-heptyne,3-heptyne, 1-octyne, 2-octyne, 3-octyne and 4-octyne. An alkynyl groupcan be unsubstituted or optionally substituted with one or moresubstituents as described herein below.

The term “alkynylene” refers to divalent alkyne. Examples of alkynyleneinclude without limitation, ethynylene, propynylene. “Substitutedalkynylene” refers to divalent substituted alkyne.

The term “alkoxy” refers to an —O-alkyl group having the indicatednumber of carbon atoms. For example, a (C₁-C₆)alkoxy group includes—O-methyl (methoxy), —O-ethyl (ethoxy), —O-propyl (propoxy),—O-isopropyl (isopropoxy), —O-butyl (butoxy), —O-sec-butyl (sec-butoxy),—O-tert-butyl (tert-butoxy), —O-pentyl (pentoxy), —O-isopentyl(isopentoxy), —O-neopentyl (neopentoxy), —O-hexyl (hexyloxy),—O-isohexyl (isohexyloxy), and —O-neohexyl (neohexyloxy).

The term “aryl,” alone or in combination refers to an aromaticmonocyclic or bicyclic ring system such as phenyl or naphthyl. “Aryl”also includes aromatic ring systems that are optionally fused with acycloalkyl ring as herein defined.

A “substituted aryl” is an aryl that is independently substituted withone or more substituents attached at any available atom to produce astable compound, wherein the substituents are as described herein.“Optionally substituted aryl” refers to aryl or substituted aryl.

“Arylene” denotes divalent aryl, and “substituted arylene” refers todivalent substituted aryl. “Optionally substituted arylene” refers toarylene or substituted arylene.

The term “heteroatom” refers to N, O, and S. Inventive compounds thatcontain N or S atoms can be optionally oxidized to the correspondingN-oxide, sulfoxide or sulfone compounds.

“Heteroaryl,” alone or in combination with any other moiety describedherein, refers to a monocyclic aromatic ring structure containing 5 or 6ring atoms, or a bicyclic aromatic group having 8 to 10 atoms,containing one or more, such as 1 to 4, 1 to 3, or 1 to 2, heteroatomsindependently selected from the group consisting of O, S, and N.Heteroaryl is also intended to include oxidized S or N, such assulfinyl, sulfonyl and N-oxide of a tertiary ring nitrogen. A carbon orheteroatom is the point of attachment of the heteroaryl ring structuresuch that a stable compound is produced. Examples of heteroaryl groupsinclude, but are not limited to, pyridinyl, pyridazinyl, pyrazinyl,quinoxalyl, indolizinyl, benzo[b]thienyl, quinazolinyl, purinyl,indolyl, quinolinyl, pyrimidinyl, pyrrolyl, pyrazolyl, oxazolyl,thiazolyl, thienyl, isoxazolyl, oxathiadiazolyl, isothiazolyl,tetrazolyl, imidazolyl, triazolyl, furanyl, benzofuryl, and indolyl.“Heteroaryl” also contemplates fused ring systems wherein the heteroarylis fused to an aryl or cycloalkyl ring as defined herein.

A “substituted heteroaryl” is a heteroaryl that is independentlysubstituted, unless indicated otherwise, with one or more, e.g., 1, 2,3, 4 or 5, attached at any available atom to produce a stable compound,wherein the substituents are as described herein. “Optionallysubstituted heteroaryl” refers to heteroaryl or substituted heteroaryl.

“Heteroarylene” refers to divalent heteroaryl, and “substitutedheteroarylene” refers to divalent substituted heteroaryl. “Optionallysubstituted heteroarylene” refers to heteroarylene or substitutedheteroarylene.

“Heterocycloalkyl” means a saturated or unsaturated non-aromaticmonocyclic, bicyclic, tricyclic or polycyclic ring system that has from5 to 14 atoms in which from 1 to 3 carbon atoms in the ring are replacedby heteroatoms of O, S or N. A heterocycloalkyl is optionally fused withbenzo or heteroaryl of 5-6 ring members, and includes oxidized S or N,such as sulfinyl, sulfonyl and N-oxide of a tertiary ring nitrogen. Thepoint of attachment of the heterocycloalkyl ring is at a carbon orheteroatom such that a stable ring is retained. Examples ofheterocycloalkyl groups include without limitation morpholino,tetrahydrofuranyl, dihydropyridinyl, piperidinyl, pyrrolidinyl,piperazinyl, dihydrobenzofuryl, and dihydroindolyl.

“Optionally substituted heterocycloalkyl” denotes heterocycloalkyl thatis substituted with 1 to 3 substituents, e.g., 1, 2 or 3 substituents,attached at any available atom to produce a stable compound, wherein thesubstituents are as described herein.

“Heteroalkyl” means a saturated alkyl group having from 1 to about 20carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 3carbon atoms, in which from 1 to 3 carbon atoms are replaced byheteroatoms of O, S or N. Heteroalkyl is also intended to includeoxidized S or N, such as sulfinyl, sulfonyl and N-oxide of a tertiaryring nitrogen. The point of attachment of the heteroalkyl substituent isat an atom such that a stable compound is formed. Examples ofheteroalkyl groups include, but are not limited to, N-alkylaminoalkyl(e.g., CH₃NHCH₂—), N,N-dialkylaminoalkyl (e.g., (CH₃)₂NCH₂—), and thelike.

“Heteroalkylene” refers to divalent heteroalkyl. The term “optionallysubstituted heteroalkylene” refers to heteroalkylene that is substitutedwith 1 to 3 substituents, e.g., 1, 2 or 3 substituents, attached at anyavailable atom to produce a stable compound, wherein the substituentsare as described herein.

“Heteroalkene” means a unsaturated alkyl group having from 1 to about 20carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 3carbon atoms, in which from 1 to 3 carbon atoms are replaced byheteroatoms of O, S or N, and having 1 to 3, 1 to 2, or at least onecarbon to carbon double bond or carbon to heteroatom double bond.

“Heteroalkenylene” refers to divalent heteroalkene. The term “optionallysubstituted heteroalkenylene” refers to heteroalkenylene that issubstituted with 1 to 3 substituents, e.g., 1, 2 or 3 substituents,attached at any available atom to produce a stable compound, wherein thesubstituents are as described herein.

The term “cycloalkyl” refer to monocyclic, bicyclic, tricyclic, orpolycyclic, 3- to 14-membered ring systems, which are either saturated,unsaturated or aromatic. The cycloalkyl group may be attached via anyatom. Cycloalkyl also contemplates fused rings wherein the cycloalkyl isfused to an aryl or hetroaryl ring as defined above. Representativeexamples of cycloalkyl include, but are not limited to cyclopropyl,cyclobutyl, cyclopentyl, and cyclohexyl. A cycloalkyl group can beunsubstituted or optionally substituted with one or more substituents asdescribed herein below.

The term “cycloalkenyl” refers to a monocyclic, bicyclic, tricyclic, orpolycyclic, 3- to 14-membered ring system, which is unsaturated. Thecycloalkenyl group may be attached via any atom. Representative examplesof cycloalkenyl include, but are not limited to, cyclopropenyl,cyclobutenyl, cyclopentenyl and cyclohexenyl.

The term “cycloalkylene” refers to divalent cycloalkyl. The term“optionally substituted cycloalkylene” refers to cycloalkylene that issubstituted with 1 to 3 substituents, e.g., 1, 2 or 3 substituents,attached at any available atom to produce a stable compound, wherein thesubstituents are as described herein.

The term ‘nitrile or cyano” can be used interchangeably and refer to a—CN group which is bound to a carbon atom of a heteroaryl ring, arylring and a heterocycloalkyl ring.

The term “oxo” refers to a ═O atom attached to a saturated orunsaturated (C₃-C₈) cyclic or a (C₁-C₈) acyclic moiety. The ═O atom canbe attached to a carbon, sulfur, and nitrogen atom that is part of thecyclic or acyclic moiety.

The term “amine or amino” refers to an —NR^(d)R^(e) group wherein R^(d)and R^(e) each independently refer to a hydrogen, (C₁-C₈)alkyl, aryl,heteroaryl, heterocycloalkyl, (C₁-C₈)haloalkyl, and (C₁-C₆)hydroxyalkylgroup.

The term “amide” refers to a —NR′R″C(O)— group wherein R′ and R″ eachindependently refer to a hydrogen, (C₁-C₈)alkyl, or (C₃-C₆)aryl.

The term “carboxamido” refers to a —C(O)NR′R″ group wherein R′ and R″each independently refer to a hydrogen, (C₁-C₈)alkyl, or (C₃-C₆)aryl.

The term “aryloxy” refers to an —O-aryl group having the indicatednumber of carbon atoms. Examples of aryloxy groups include, but are notlimited to, phenoxy, napthoxy and cyclopropeneoxy.

The term “haloalkoxy,” refers to an —O—(C₁-C₆)alkyl group wherein one ormore hydrogen atoms in the C₁-C₈ alkyl group is replaced with a halogenatom, which can be the same or different. Examples of haloalkyl groupsinclude, but are not limited to, difluoromethoxy, trifluoromethoxy,2,2,2-trifluoroethoxy, 4-chlorobutoxy, 3-bromopropyloxy,pentachloroethoxy, and 1,1,1-trifluoro-2-bromo-2-chloroethoxy.

The term “hydroxyalkyl,” refers to an alkyl group having the indicatednumber of carbon atoms wherein one or more of the alkyl group's hydrogenatoms is replaced with an —OH group. Examples of hydroxyalkyl groupsinclude, but are not limited to, —CH₂OH, —CH₂CH₂OH, —CH₂CH₂CH₂OH,—CH₂CH₂CH₂CH₂OH, —CH₂CH₂CH₂CH₂CH₂OH, —CH₂CH₂CH₂CH₂CH₂CH₂OH, and branchedversions thereof.

The term “alkylsulfonyl” refers to a (C₁-C₆)alkyl group wherein one ormore hydrogen atoms in the C₁-C₆ alkyl group is replaced with a—S(O)_(a) group. Subscript “a” can either be 1 or 2, so as to give analkyl sulfoxide (sulfinyl group), or an alkyl sulfone respectively.Examples of alkylsulfonyl groups include, but are not limited todimethylsulfoxide, ethylmethyl sulfoxide, and methylvinylsulfone.

The term “haloalkyl,” refers to an (C₁-C₆)alkyl group wherein one ormore hydrogen atoms in the C₁-C₆ alkyl group is replaced with a halogenatom, which can be the same or different. Examples of haloalkyl groupsinclude, but are not limited to, difluoromethyl, trifluoromethyl,2,2,2-trifluoroethyl, 4-chlorobutyl, 3-bromopropylyl, pentachloroethyl,and 1,1,1-trifluoro-2-bromo-2-chloroethyl.

The term “aminoalkyl,” refers to an (C₁-C₆)alkyl group wherein one ormore hydrogen atoms in the C₁-C₆ alkyl group is replaced with a—NR^(d)R^(e) group, where R^(d) and R^(e) can be the same or different,for example, R^(d) and R^(e) each independently refer to a hydrogen,(C₁-C₈)alkyl, aryl, heteroaryl, heterocycloalkyl, (C₁-C₈)haloalkyl, and(C₁-C₆)hydroxyalkyl group. Examples of aminoalkyl groups include, butare not limited to, aminomethyl, aminoethyl, 4-aminobutyl and3-aminobutylyl.

The term “thioalkyl” or “alkylthio” refers to a (C₁-C₆)alkyl groupwherein one or more hydrogen atoms in the C₁-C₆ alkyl group is replacedwith a —SR^(j) group, wherein R^(j) is selected from the groupconsisting of hydrogen, (C₁-C₆)alkyl and (C₃-C₁₄)aryl.

“Amino (C₁-C₆)alkylene” refers to a divalent alkylene wherein one ormore hydrogen atoms in the C₁-C₆ alkylene group is replaced with a—NR^(d)R^(e) group. Examples of amino (C₁-C₆)alkylene include, but arenot limited to, aminomethylene, aminoethylene, 4-aminobutylene and3-aminobutylylene.

The term “sulfonamide” refers to an —NR^(g)S(O)₂R^(h) group where R^(g)and R^(h) are each independently refer to a hydrogen, (C₁-C₈)alkyl,aryl, heteroaryl, heterocycloalkyl, (C₁-C₈)haloalkyl, and(C₁-C₆)hydroxyalkyl group.

A “hydroxyl” or “hydroxy” refers to an —OH group.

The term “(C₃-C₁₄)aryl-(C₁-C₆)alkylene” refers to a divalent alkylenewherein one or more hydrogen atoms in the C₁-C₆ alkylene group isreplaced by a (C₃-C₁₄)aryl group. Examples of(C₃-C₁₄)aryl-(C₁-C₆)alkylene groups include without limitation1-phenylbutylene, phenyl-2-butylene, 1-phenyl-2-methylpropylene,phenylmethylene, phenylpropylene, and naphthyl ethylene.

The term “(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene” refers to a divalentalkylene wherein one or more hydrogen atoms in the C₁-C₆ alkylene groupis replaced a (C₃-C₁₄)heteroaryl group. Examples of(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene groups include without limitation1-pyridylbutylene, quinolinyl-2-butylene and1-pyridyl-2-methylpropylene.

The term “(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene” refers to a divalentalkylene wherein one or more hydrogen atoms in the C₁-C₆ alkylene groupis replaced by a (C₃-C₁₄)heterocycloalkyl group. Examples of(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene groups include withoutlimitation 1-morpholinopropylene, azetidinyl-2-butylene and 1-tetrahydrofuranyl-2-methylpropylene.

The term “(C₃-C₁₄)heteroaryl-(C₁-C₁₄)heterocycloalkylene” refers to adivalent heterocycloalkylene wherein one or more hydrogen atoms in theC₁-C₆ heterocycloalkylene group is replaced by a (C₃-C₁₄)heteroarylgroup. Examples of (C₃-C₁₄)heteroaryl-(C₁-C₆)heterocycloalkylene groupsinclude without limitation pyridylazetidinylene and4-quinolino-1-piperazinylene.

The term “(C₃-C₁₄)aryl-(C₁-C₁₄)heterocycloalkylene” refers to a divalentheterocycloalkylene wherein one or more hydrogen atoms in the C₁-C₁₄heterocycloalkylene group is replaced by a (C₃-C₁₄)aryl group. Examplesof (C₃-C₁₄)aryl-(C₁-C₁₄)heterocycloalkylene groups include withoutlimitation 1-naphthyl-piperazinylene, phenylazetidinylene, andphenylpiperidinylene.

The term “(C₃-C₁₄)aryl-(C₁-C₆)alkyl-(C₁-C₁₄)heterocycloalkylene” refersto a divalent heterocycloalkylene wherein one or more hydrogen atoms inthe C₁-C₁₄ heterocycloalkylene group is replaced by a (C₁-C₆) alkylgroup that is further substituted by replacing one or more hydrogenatoms of the (C₁-C₆) alkyl group with a (C₃-C₁₄)aryl group.

The term “(C₃-C₁₄)heteroaryl-(C₁-C₆)alkyl-(C₁-C₁₄)heterocycloalkylene”refers to a divalent heterocycloalkylene wherein one or more hydrogenatoms in the C₁-C₁₄ heterocycloalkylene group is replaced by a (C₁-C₆)alkyl group that is further substituted by replacing one or morehydrogen atoms of the (C₁-C₆) alkyl group with a (C₃-C₁₄)heteroarylgroup.

The term“(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkyl-(C₁-C₁₄)heterocycloalkylene”refers to a divalent heterocycloalkylene wherein one or more hydrogenatoms in the C₁-C₁₄ heterocycloalkylene group is replaced by a (C₁-C₆)alkyl group that is further substituted by replacing one or morehydrogen atoms of the (C₁-C₆) alkyl group with a(C₃-C₁₄)heterocycloalkyl group.

The term “(C₃-C₁₄)aryl-(C₁-C₁₄)cycloalkylene” refers to a divalentcycloalkylene that is monocyclic, bicyclic or polycyclic and wherein oneor more hydrogen atoms in the (C₁-C₁₄)cycloalkylene group is replaced bya (C₃-C₁₄)aryl group. Examples of (C₃-C₁₄)aryl-(C₁-C₁₄)cycloalkylenegroups include without limitation phenylcyclobutylene,phenyl-cyclopropylene and 3-phenyl-2-methylbutylene-1-one.

The substituent —CO₂H, may be replaced with bioisosteric replacementssuch as:

and the like, wherein R has the same definition as R′ and R″ as definedherein. See, e.g., THE PRACTICE OF MEDICINAL CHEMISTRY (Academic Press:New York, 1996), at page 203.

The compound of the invention can exist in various isomeric forms,including configurational, geometric, and conformational isomers,including, for example, cis- or trans-conformations. Compounds of thepresent invention may also exist in one or more tautomeric forms,including both single tautomers and mixtures of tautomers. The term“isomer” is intended to encompass all isomeric forms of a compound ofthis invention, including tautomeric forms of the compound.

The compounds of the present invention may also exist in open-chain orcyclized forms. In some cases one or more of the cyclized forms mayresult in loss of water. The specific composition of the open-chain andcyclized forms may be dependent on how the compound is isolated, storedor administered. For example the compound may exist primarily in anopen-chained form under acidic conditions but cyclize under neutralconditions. All forms are included in the invention.

Some compounds described here can have asymmetric centers and thereforeexist in different enantiomeric and diastereomeric forms. A compound ofthe invention can be in the form of an optical isomer or a diastereomer.Accordingly, the invention encompasses compounds of the invention andtheir uses as described herein in the form of their optical isomers,diastereoisomers and mixtures thereof, including a racemic mixture.Optical isomers of the compounds of the invention can be obtained byknown techniques such as asymmetric synthesis, chiral chromatography,simulated moving bed technology or via chemical separation ofstereoisomers through the employment of optically active resolvingagents.

Unless otherwise indicated, “stereoisomer” means one stereoisomer of acompound that is substantially free of other stereoisomers of thatcompound. Thus, a stereomerically pure compound having one chiral centerwill be substantially free of the opposite enantiomer of the compound. Astereomerically pure compound having two chiral centers will besubstantially free of other diastereomers of the compound. A typicalstereomerically pure compound comprises greater than about 80% by weightof one stereoisomer of the compound and less than about 20% by weight ofother stereoisomers of the compound, for example greater than about 90%by weight of one stereoisomer of the compound and less than about 10% byweight of the other stereoisomers of the compound, or greater than about95% by weight of one stereoisomer of the compound and less than about 5%by weight of the other stereoisomers of the compound, or greater thanabout 97% by weight of one stereoisomer of the compound and less thanabout 3% by weight of the other stereoisomers of the compound.

If there is a discrepancy between a depicted structure and a name givento that structure, then the depicted structure controls. Additionally,if the stereochemistry of a structure or a portion of a structure is notindicated with, for example, bold or dashed lines, the structure orportion of the structure is to be interpreted as encompassing allstereoisomers of it. In some cases, however, where more than one chiralcenter exists, the structures and names may be represented as singleenantiomers to help describe the relative stereochemistry. Those skilledin the art of organic synthesis will know if the compounds are preparedas single enantiomers from the methods used to prepare them.

A “pharmaceutically acceptable salt” is a pharmaceutically acceptable,organic or inorganic acid or base salt of a compound of the invention.Representative pharmaceutically acceptable salts include, e.g., alkalimetal salts, alkali earth salts, ammonium salts, water-soluble andwater-insoluble salts, such as the acetate, amsonate(4,4-diaminostilbene-2,2-disulfonate), benzenesulfonate, benzonate,bicarbonate, bisulfate, bitartrate, borate, bromide, butyrate, calcium,calcium edetate, camsylate, carbonate, chloride, citrate, clavulariate,dihydrochloride, edetate, edisylate, estolate, esylate, fumarate,gluceptate, gluconate, glutamate, glycollylarsanilate,hexafluorophosphate, hexylresorcinate, hydrabamine, hydrobromide,hydrochloride, hydroxynaphthoate, iodide, isothionate, lactate,lactobionate, laurate, malate, maleate, mandelate, mesylate,methylbromide, methylnitrate, methylsulfate, mucate, napsylate, nitrate,N-methylglucamine ammonium salt, 3-hydroxy-2-naphthoate, oleate,oxalate, palmitate, pamoate (1,1-methene-bis-2-hydroxy-3-naphthoate,einbonate), pantothenate, phosphate/diphosphate, picrate,polygalacturonate, propionate, p-toluenesulfonate, salicylate, stearate,subacetate, succinate, sulfate, sulfosalicylate, suramate, tannate,tartrate, teoclate, tosylate, triethiodide, and valerate salts. Apharmaceutically acceptable salt can have more than one charged atom inits structure. In this instance the pharmaceutically acceptable salt canhave multiple counterions. Thus, a pharmaceutically acceptable salt canhave one or more charged atoms and/or one or more counterions.

The terms “treat”, “treating” and “treatment” refer to the ameliorationor eradication of a disease or symptoms associated with a disease. Incertain embodiments, such terms refer to minimizing the spread orworsening of the disease resulting from the administration of one ormore prophylactic or therapeutic agents to a patient with such adisease.

The terms “prevent,” “preventing,” and “prevention” refer to theprevention of the onset, recurrence, or spread of the disease in apatient resulting from the administration of a prophylactic ortherapeutic agent.

The term “effective amount” refers to an amount of a compound of theinvention, such as a Formula I or Formula II compound, or other activeingredient sufficient to provide a therapeutic or prophylactic benefitin the treatment or prevention of a disease or to delay or minimizesymptoms associated with a disease. Further, a therapeutically effectiveamount with respect to a compound of the invention means that amount oftherapeutic agent alone, or in combination with other therapies, thatprovides a therapeutic benefit in the treatment or prevention of adisease. Used in connection with a compound of the invention, the termcan encompass an amount that improves overall therapy, reduces or avoidssymptoms or causes of disease, or enhances the therapeutic efficacy ofor synergies with another therapeutic agent.

The terms “modulate”, “modulation” and the like refer to the ability ofa Formula I or Formula II compound to increase or decrease the function,or activity of, for example, Arginase I or Arginase II. “Modulation”, inits various forms, is intended to encompass inhibition, antagonism,partial antagonism, activation, agonism and/or partial agonism of theactivity associated with arginase. Arginase inhibitors are compoundsthat, e.g., bind to, partially or totally block stimulation, decrease,prevent, delay activation, inactivate, desensitize, or down regulatesignal transduction. The ability of a compound to modulate arginaseactivity can be demonstrated in an enzymatic assay or a cell-basedassay.

A “patient” includes an animal, such as a human, cow, horse, sheep,lamb, pig, chicken, turkey, quail, cat, dog, mouse, rat, rabbit orguinea pig. The animal can be a mammal such as a non-primate and aprimate (e.g., monkey and human). In one embodiment, a patient is ahuman, such as a human infant, child, adolescent or adult.

The term “prodrug” refers to a precursor of a drug that is a compoundwhich upon administration to a patient, must undergo chemical conversionby metabolic processes before becoming an active pharmacological agent.Exemplary prodrugs of compounds in accordance with Formula I and II areesters, pinenes, dioxaborolanes, and amides.

Formula I Compounds

As described above, the present invention relates to compounds accordingto Formula I.

For Formula I compounds, D is selected from the group consisting ofstraight or branched (C₁-C₆)alkylene, straight or branched(C₂-C₈)alkenylene, straight or branched (C₂-C₈)alkynylene,(C₃-C₁₄)arylene, and (C₃-C₁₄)cycloalkylene. In some embodiments, one ormore —CH₂— groups in D are optionally and independently replaced with amoiety selected from group the consisting of —O—, —NR′—, —S—, —SO—,—SO₂—, and —CR′R″—. For instance, D can be a four atom linker having theformula -L¹-L²-CH₂—CH₂—, —CH₂-L¹-L²-CH₂—, —CH₂—CH₂-L¹-L²-,-L¹-CH₂—CH₂-L²-, -L¹-CH₂-L²-CH₂—, or -L¹-CH₂—CH₂-L²-. The variables L¹and L² are independently selected from the group consisting of O, NR′,S, SO, SO₂, and CR′R″, wherein R′ and R″ are as defined above.

In other embodiments, D contains a (C₃-C₁₄)-cycloalkylenyl ring, tworing members of which are two adjacent —CH₂— groups in D, each having ahydrogen atom removed. A specific example of D is n-butylene wherein thesecond and third carbon atoms are part of a cyclopropyl group, as shownin the moiety

Variable D is advantageously a three to five atom linker. A particularlyadvantageous embodiment provides for D as a four atom linker asdescribed herein.

In one embodiment, for example, the invention provides Formula Icompounds in which D is butylene, R¹ is —OH, each of R³, R⁴ and R⁵ arehydrogen and R² is selected from the group consisting of (C₁-C₆)alkyl,(C₃-C₁₄)aryl, (C₃-C₁₄)heteroaryl, (C₃-C₁₄)heterocycloalkyl,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene-,(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene-, (C₃-C₁₄)aryl-(C₁-C₆)alkylene-and —(CH₂)_(n)—(X)_(u)—(CH₂)_(m)—(Y)_(v)—R^(f).

In another embodiment, R² is —(CH₂)_(n)—(X)_(u)—(CH₂)_(m)—(Y)_(v)—R_(f).X and Y are each independently —NH, subscripts m and n are 1 and 2respectively and u and v are both 1.

Alternatively, R² can be an alkyl group that is optionally substitutedby hydroxyl or —NR^(d)R^(e), where each of R^(d) and R^(e) areindependently selected from the group consisting of H, straight orbranched (C₁-C₆)alkyl, (C₁-C₆)aminoalkyl, optionally substituted(C₃-C₁₄)aryl(C₁-C₆)alkylene-, optionally substituted (C₃-C₁₄)aryl, andoptionally substituted (C₃-C₆) cycloalkyl. For example, when R² is anaminoalkyl, each of R^(d) and R^(e) can be a (C₁-C₆)aminoalkyl.

In another embodiment, R² can be a(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene-, for example, a(C₃-C₆)heterocycloalkyl-(C₁-C₂)alkylene-. Suitable(C₃-C₆)heterocycloalkyls include azetidinyl, pyrrolidinyl, piperidinyl,piperazinyl, morpholinyl, tetrahydro-2H-pyran, and thiomorpholinyl. The(C₃-C₆)heterocycloalkyl can optionally be substituted with one or moremembers selected from the group consisting of —(C₁-C₆)alkoxy,—(C₁-C₆)alkyl, and —OH. In one embodiment, the (C₃-C₆)heterocycloalkylcan be piperidinyl or pyrrolidinyl and the —(C₁-C₆)alkylene- can bemethylene or ethylene.

For Formula I compounds, when R² is (C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene-,R² can be a (C₃-C₆)heteroaryl-(C₁-C₆)alkylene- group. Exemplary(C₃-C₆)heteroaryl groups without limitation include pyridinyl,benzimidazolyl, benzothiazol, imidazole, 1,2,3-triazole, 1,2,4-triazole,tetrazole, pyrimidine, imidazo[1,2-a]pyridine, oxazole, isoxazole, andfuran. In an embodiment of the invention, the —(C₁-C₆)alkylene- can bemethylene, or ethylene.

In some embodiments, R³ and R⁴ together with the boron atom to whichthey are bound form a 5- or 6-membered ring that is fully or partiallysaturated, and that optionally contains 1-3 additional heteroatom ringmembers selected from O, S, and N. The ring is optionally substitutedwith one or more substituents as defined herein for R′ and R″.

Cyclic structures of this type are useful as prodrug forms of theinventive compounds by virtue of R³ and R⁴ forming a cyclic ester fromdiols. A useful diol in this regard is pinacol, and another diol ispinanediol. Other diols include but are not limited to neopentylglycol,1,2-ethanediol, 1,2-propoanediol, 1,3-propanediol, 2,3-butanediol,1,2-diisopropylethanediol and 5,6-decanediol.

Also contemplated are compounds wherein the boronic acid moiety inFormula I is esterified with a sugar. Compounds of this class are alsouseful as prodrugs. Suitable sugars include without limitationmonosaccharides and disaccharides, for example, sugars selected from thegroup consisting of glucose, mannitol and sorbitol.

In other embodiments, R² is a (C₃-C₁₄)-cycloalkyl, optionallysubstituted by 1-3 substituents as defined hereinabove. Exemplarycycloalkyl groups are cyclohexyl and cyclopentyl. Alternatively, R² is a(C₃-C₁₄)heterocycloalkyl, such as five- or six-memberedheterocycloalkyl. Examples of Formula I compounds of these embodimentsinclude those in the following table, wherein R′ is defined as above, Rhas the same meaning as R′, and W is a heteroatom as defined above:

It should be understood that 2-amino-4-borono-2-methylbutanoic acid isexcluded from Formula I.

Exemplary Formula I compounds include without limitation compoundsmentioned in Table 1 below. While some exemplary compounds are depictedwith stereochemistry, it should be understood that the inventionincludes all possible stereoisomers, such as diastereomers, of thecompounds.

TABLE 1 Ex. Structure Name 1

(R)-2-amino-6-borono-2- (2-((S)-3-(hydroxymethyl)-3,4-dihydroisoquinolin-2(1H)- yl)ethyl)hexanoic acid 2

(R)-2-amino-6-borono-2-(2-((S)-2- (methoxymethyl)pyrrolidin-1-yl)ethyl)hexanoic acid 3

(R)-2-amino-6-borono-2-(2-((R)-2- (methoxymethyl)pyrrolidin-1-yl)ethyl)hexanoic acid 4

(R)-2-amino-6-borono-2- (2-(4-hydroxypiperidin-1- yl)ethyl)hexanoic acid5

(R)-2-amino-6-borono-2- (2-((S)-3-hydroxypiperidin- 1-yl)ethyl)hexanoicacid 6

(R)-2-amino-6-borono-2-(2-((3,4-dimethoxyphenethyl)(methyl)amino)ethyl)hex- anoic acid 7

(R)-2-amino-6-borono-2-(2-((R)-3- (hydroxymethyl)pyrrolidin-1-yl)ethyl)hexanoic acid 8

(R)-2-amino-6-borono-2-(2- thiomorpholinoethyl)hexanoic acid 9

(R)-2-amino-6-borono-2-(2-(4-(2-hydroxyethyl)piperidin-1-yl)ethyl)hexanoic acid 10

(R)-2-amino-6-borono-2-(2-((S)-2- (hydroxymethyl)pyrrolidin-1-yl)ethyl)hexanoic acid 11

(R)-2-amino-6-borono-2-(2- (methyl(phenethyl)amino)ethyl)hexanoic acid12

(R)-2-amino-6-borono-2- (2-(((S)-2-hydroxy-2-(3-hydroxyphenyl)ethyl)(methyl)amino)ethyl)hex- anoic acid 13

(R)-2-amino-6-borono-2-(2-(piperidin-1- yl)ethyl)hexanoic acid 14

2-allyl-2-amino-6-boronohexanoic acid 15

(S)-2-amino-6-borono-2-ethylhexanoic acid 16

2-amino-6-borono-2-(2-(pyrrolidin-1- yl)ethyl)hexanoic acid 17

2-amino-6-borono-2-(2- (4-(pyrimidin-2-yl)piperazin- 1-yl)ethyl)hexanoicacid 18

2-amino-6-borono-2-(2- ((carboxymethyl)(methyl)amino)ethyl)hexanoic acid19

2-amino-2-(2-(benzyl(ethyl)amino)ethyl)-6- boronohexanoic acid 20

2-amino-2-(2-(benzyl(2- hydroxyethyl)amino)ethyl)- 6-boronohexanoic acid21

1-(3-amino-7-borono-3- carboxyheptyl)piperidine-4- carboxylic acid 22

2-amino-6-borono-2-(2-(4- (hydroxymethyl)piperidin-1-yl)ethyl)hexanoicacid 23

2-amino-6-borono-2-(2-(3- (diethylcarbamoyl)piperidin-1-yl)ethyl)hexanoic acid 24

2-amino-6-borono-2- (2-morpholinoethyl)hexanoic acid 25

2-amino-2-(2-(4-benzylpiperidin-1-yl)ethyl)-6- boronohexanoic acid 26

2-amino-6-borono-2-(2-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)hexanoic acid 27

2-amino-6-borono-2-(2-((4- methoxybenzyl)(methyl)amino)ethyl)hexanoicacid 28

2-amino-6-borono-2-(2-(4-phenyl-5,6-dihydropyridin-1(2H)-yl)ethyl)hexanoic acid 29

2-amino-6-borono-2-(2-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl)ethyl)hexanoic acid 30

2-amino-6-borono-2-(2-(3-oxo-2,3,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridin-5(4H)- yl)ethyl)hexanoic acid 31

2-amino-6-borono-2-(2- (4-(4-methoxyphenyl)-5,6- dihydropyridin-1(2H)-yl)ethyl)hexanoic acid 32

2-amino-6-borono-2-(2-(piperazin-1- yl)ethyl)hexanoic acid 33

2-amino-6-borono-2-(2-((S)-2- (methoxymethyl)pyrrolidin-1-yl)ethyl)hexanoic acid 34

2-amino-2-(2-(4-benzyl- 4-hydroxypiperidin-1- yl)ethyl)-6-boronohexanoicacid 35

2-amino-6-borono-2-(2-(4-methylpiperazin-1- yl)ethyl)hexanoic acid 36

2-amino-6-borono-2-(2-(3,4-dihydroisoquinolin- 2(1H)-yl)ethyl)hexanoicacid 37

2-amino-6-borono-2-(2- (diethylamino)ethyl)hexanoic acid 38

2-amino-6-borono-2-(2-(4-oxopiperidin-1- yl)ethyl)hexanoic acid 39

2-amino-6-borono-2-(2-(4- (trifluoromethyl)piperidin-1-yl)ethyl)hexanoic acid 40

2-amino-6-borono-2-(2-((S)-2-(pyrrolidin-1-ylmethyl)pyrrolidin-1-yl)ethyl)hexanoic acid 41

2-amino-6-borono-2-(2-(4-methoxypiperidin-1- yl)ethyl)hexanoic acid 42

2-amino-2-(2-(2-(benzofuran-2-yl)pyrrolidin-1-yl)ethyl)-6-boronohexanoic acid 43

2-amino-6-borono-2-(2-((2- hydroxyethyl)(methyl)amino)ethyl)hexanoicacid 44

2-amino-6-borono-2-(2-(3,3-difluoropyrrolidin-1- yl)ethyl)hexanoic acid45

2-(2-(4-acetyl-4-phenylpiperidin- 1-yl)ethyl)-2-amino- 6-boronohexanoicacid 46

2-amino-6-borono-2-(2-((R)-2- (trifluoromethyl)pyrrolidin-1-yl)ethyl)hexanoic acid 47

2-amino-6-borono-2-(2-(4-fluoropiperidin-1- yl)ethyl)hexanoic acid 48

2-amino-6-borono-2-(2-((4-fluoro-3-(trifluoromethyl)benzyl)(methyl)amino)ethyl)- hexanoic acid 49

2-amino-6-borono-2-(2- (3-methyl-1,3-diazepan-1- yl)ethyl)hexanoic acid50

2-amino-6-borono-2-(2-(4-(2- methoxyphenyl)piperazin-1-yl)ethyl)hexanoicacid 51

2-amino-2-(2-(bis(2-aminoethyl)amino)ethyl)-6- boronohexanoic acid 52

1-(3-amino-7-borono-3- carboxyheptyl)piperidine-2- carboxylic acid 53

(3R)-1-(3-amino-7-borono-3- carboxyheptyl)piperidine-3-carboxylic acid54

2-amino-6-borono-2-(2-((S)-2- (dimethylcarbamoyl)pyrrolidin-1-yl)ethyl)hexanoic acid 55

2-amino-6-borono-2-(2- (isopropylamino)ethyl)hexanoic acid 56

(3S)-1-(3-amino-7-borono-3- carboxyheptyl)piperidine-3-carboxylic acid57

1-(3-amino-7-borono-3-carboxyheptyl)-4- methylpiperidine-4-carboxylicacid 58

2-amino-6-borono-2-(2-(2,3-dihydro-1H-inden-2- ylamino)ethyl)hexanoicacid 59

2-amino-6-borono-2-(2-(3-hydroxyazetidin-1- yl)ethyl)hexanoic acid 60

2-amino-6-borono-2-(2-(1- butylcyclopropylamino)ethyl)hexanoic acid 61

2-amino-6-borono-2-(2-(1-(4- methoxybenzyl)cyclopropylamino)ethyl)hex-anoic acid 62

2-amino-6-borono-2-(2-(4,5-dihydrothieno[2,3-c]pyridin-6(7H)-yl)ethyl)hexanoic acid 63

2-amino-6-borono-2-(2-(3-(3,4- difluorophenyl)propylamino)ethyl)hexanoicacid 64

2-amino-6-borono-2-(2-(3-(2-chloro-5-(trifluoromethyl)phenyl)propylamino)ethyl)hex- anoic acid 65

2-amino-6-borono-2-(2-(3-(3- methoxyphenyl)propylamino)ethyl)hexanoicacid 66

2-amino-6-borono-2-(2-(3-(2,4- dichlorophenyl)propylamino)ethyl)hexanoicacid 67

2-amino-6-borono-2-(2-(tert- butylamino)ethyl)hexanoic acid 68

2-amino-6-borono-2-(2- (cyclopropylamino)ethyl)hexanoic acid 69

2-amino-6-borono-2-(2-(4- methoxybenzylamino)ethyl)hexanoic acid 70

2-amino-2-(2-(benzylamino)ethyl)- 6-boronohexanoic acid 71

2-amino-6-borono-2-(2-((2-(dimethylamino)ethyl)(methyl)amino)ethyl)hexanoic acid 72

2-amino-6-borono-2-(2- (cyclopentylamino)ethyl)hexanoic acid 73

2-amino-2-(2-((2-aminoethyl)(benzypamino)ethyl)-6- boronohexanoic acid74

2-amino-6-borono-2-(2-(4- isopropoxybenzyl)(methyl)amino)ethyl)hex-anoic acid 75

2-amino-2-(2-(azetidin-1-yl)ethyl)-6-boronohexanoic acid 76

2-amino-6-borono-2-(2-(4-phenylpiperazin-1- yl)ethyl)hexanoic acid 77

2-amino-6-borono-2-(2-(4-(2- methoxyethyl)piperazin-1-yl)ethyl)hexanoicacid 78

2-amino-6-borono-2-(2-((2-hydroxy-2-phenylethyl)(methyl)amino)ethyl)hexanoic acid 79

2-amino-6-borono-2-(piperidin-1-ylmethyl)hexanoic acid 80

2-amino-6-borono-2-((4-methylpiperazin-1- yl)methyl)hexanoic acid 81

2-amino-6-borono-2-(morpholinomethyl)hexanoic acid 82

2-amino-6-borono-2-(hydroxymethyl)hexanoic acid 83

2-amino-6-borono-2-((propylamino)methyl)hexanoic acid 84

2-amino-2-((benzylamino)methyl)-6-boronohexanoic acid 85

2-amino-6-borono-2-(((R)-2- hydroxypropylamino)methyl)hexanoic acid 86

2-amino-6-borono-2-((butylamino)methyl)hexanoic acid 87

2-amino-6-borono-2-((tetrahydro-2H-pyran-4- ylamino)methyl)hexanoic acid88

2-amino-6-borono-2-(((S)-1-hydroxy-4-methylpentan-2-ylamino)methyl)hexanoic acid 89

2-amino-6-borono-2-(((1S,2R)-2-hydroxy-1,2-diphenylethylamino)methyl)hexanoic acid 90

2-amino-6-borono-2-(((S)-1- phenylethylamino)methyl)hexanoic acid 91

2-amino-6-borono-2-(2-(((R)-1-hydroxypropan-2- ylamino)ethyl)hexanoicacid 92

2-amino-6-borono-2-(2-(4- chlorophenoxy)ethyl)hexanoic acid 93

2-amino-6-borono-2-(2-(4- methoxyphenoxy)ethyl)hexanoic acid 94

2-amino-6-borono-2-(2-(2,4- dichlorophenoxy)ethyl)hexanoic acid 95

2-amino-6-borono-2-(2-(3- (trifluoromethyl)phenoxy)ethyl)hexanoic acid96

2-amino-6-borono-2-(3-(4- chlorophenoxy)propyl)hexanoic acid 97

2-amino-6-borono-2-methylhexanoic acid 98

2-amino-6-borono-2-(3-fluorobenzyl)hexanoic acid 99

2-amino-2-benzyl-6-boronohexanoic acid 100

2-amino-6-borono-2-(3-methoxypropyl)hexanoic acid 101

2-amino-6-borono-2-(3-hydroxypropyl)hexanoic acid 102

2-((1H-imidazol-4-yl)methyl)-2-amino-6- boronohexanoic acid 103

2-(4-boronobutyl)pyrrolidine-2-carboxylic acid 104

2-amino-6-borono-2-isobutylhexanoic acid 105

2-amino-6-borono-2-isopropylhexanoic acid 106

2-amino-2-(4-boronobutyl)succinic acid 107

2-amino-6-borono-2-((1-isopropyl-1H-imidazol-5- yl)methyl)hexanoic acid108

2-amino-6-borono-2-(1-hydroxypropyl)hexanoic acid 109

2-amino-6-borono-2-(hydroxy(piperidin-4- yl)methyl)hexanoic acid 110

2-amino-6-borono-2-(hydroxy(piperidin-3- yl)methyl)hexanoic acid 111

2-amino-2-(4-boronobutyl)-6,6,6-trifluoro-3- hydroxyhexanoic acid 112

2-amino-6-borono-2-(hydroxy(pyridin-3- yl)methyl)hexanoic acid 113

2-amino-2-(azetidin-3-yl(hydroxy)methyl)-6- boronohexanoic acid 114

5-amino-6-oxo-6-phenylhexylboronic acid 115

(R)-2-amino-6-borono-2-((R)-pyrrolidin-2- ylmethyl)hexanoic acid 116

2-amino-6-borono-2-(2-(pyridin-2-yl)ethyl)hexanoic acid 117

2-amino-6-borono-2-((1-(3,4-dichlorobenzyl)azetidin-3-yl)methyl)hexanoic acid 118

2-amino-6-borono-2-((1-(2,4- dichlorophenethyl)azetidin-3-yl)methyl)hexanoic acid 119

2-amino-6-borono-2-(2-(3-(3,4- dichlorophenyl)thioureido)ethyl)hexanoicacid 120

2-amino-6-borono-2-(2-isobutyramidoethyl)hexanoic acid 121

2-amino-6-borono-2-(2-(4-(4-chlorophenyl)piperidin- 1-yl)ethyl)hexanoicacid 122

2-amino-6-borono-2-(2-(4-(4-chlorobenzyl)piperidin- 1-yl)ethyl)hexanoicacid 123

2-amino-2-(azetidin-3-ylmethyl)-6-boronohexanoic acid 124

2-amino-2-(2-(4-benzylpiperidin-1-yl)propyl)-6- boronohexanoic acid 125

2-amino-2-(2-(4-benzylpiperidin-1-yl)ethyl)-6- boronohexanoic acid 126

2-amino-6-borono-2-(2-(4-(4- (trifluoromethyl)benzyl)piperidin-1-yl)ethyl)hexanoic acid 127

2-amino-6-borono-2-(2-(4-(4-fluorobenzyl)piperidin- 1-yl)ethyl)hexanoicacid 128

2-amino-6-borono-2-(2-(4,4-dimethylpiperidin-1- yl)ethyl)hexanoic acid129

2-amino-6-borono-2-(2-(4-propylpiperidin-1- yl)ethyl)hexanoic acid 130

2-amino-6-borono-2-(2-(2-ethyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoic acid 131

2-amino-6-borono-2-(2-(1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoic acid 132

2-amino-6-borono-2-(2-(2-(4-chlorobenzyl)-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoic acid 133

2-amino-6-borono-2-(2-(2-isopentyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoic acid 134

2-amino-6-borono-2-(2-(2-(cyclohexylmethyl)-1,2,3,4-tetrahydroisoquinolin-3- yl)ethyl)hexanoic acid 135

2-amino-6-borono-2-(2-(2-isobutyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoic acid 136

6-borono-2-(3-(3,4-dichlorobenzylamino)propyl)-2- (methylamino)hexanoicacid 137

6-borono-2-(methylamino)-2-(3-(pyrrolidin-1- yl)propyl)hexanoic acid 138

6-borono-2-(3-(2,3-dihydro-1H-inden-2-ylamino)propyl)-2-(methylamino)hexanoic acid 139

6-borono-2-(3-(4-chlorobenzylamino)propyl)-2- (methylamino)hexanoic acid140

2-amino-6-borono-2-(3-(2,4- dichlorophenethylamino)propyl)hexanoic acid141

2-amino-6-borono-2-(3-(3,4- dichlorobenzylamino)propyl)hexanoic acid 142

2-amino-6-borono-2-(2-(4-(4-chlorobenzyl)piperidin- 1-yl)ethyl)hexanoicacid 143

2-amino-6-borono-2-(2-((S)-pyrrolidin-2- yl)ethyl)hexanoic acid 144

6-borono-2-(methylamino)-2-(2-((S)-pyrrolidin-2- yl)ethyl)hexanoic acid145

6-borono-2-(4-chlorobenzylamino)hexanoic acid 146

6-borono-2-(methylamino)hexanoic acid 147

2-amino-6-borono-2-(3-(piperidin-1- yl)propyl)hexanoic acid 148

6-borono-2-(methylamino)-2-(3-(piperidin-1- yl)propyl)hexanoic acid 149

6-borono-2-(methylamino)-2-(2-(piperidin-1- yl)ethyl)hexanoic acidFormula II Compounds

The present invention also relates to compounds according to Formula II.

For compounds that conform to Formula II, D is selected from the groupconsisting of straight or branched (C₃-C₅)alkylene, straight or branched(C₂-C₈)alkenylene, straight or branched (C₂-C₈)alkynylene,(C₃-C₁₄)arylene, and (C₃-C₁₄)cycloalkylene. In one embodiment one ormore —CH₂— groups in D are optionally and independently replaced with amoiety selected from the group consisting of O, NR′, S, SO, SO₂, andCR′R″. However, no two adjacent —CH₂— groups in D are simultaneouslyreplaced by O, NR′, S, SO, or SO₂.

According to one embodiment, D conforms to formula -L¹-L²-CH₂—CH₂—,—CH₂-L¹-L²-CH₂—, —CH₂—CH₂-L¹-L²-, -L¹-CH₂—CH₂-L²-, -L¹-CH₂—CH₂—, or—CH₂-L¹-CH₂-L²-. While variables L¹ and L² are each independentlyselected from the group consisting of O, NR′, S, SO, SO₂, and CR′R″,when -L¹ and -L² are adjacent to each other L¹ and L² are notsimultaneously O, NR′, S, SO or a SO₂ group.

For certain Formula II compounds, any two adjacent —CH₂— groups in Doptionally represent two members of a (C₃-C₁₄)-cycloalkylenyl group.Thus, for instance, when D is propylene the C₂ and C₃ atom can each omita hydrogen atom so as to couple a —CH₂— group to form a cyclopropyl ringas illustrated by the following moiety

Variable D is advantageously a three to five atom linker. A particularlyadvantageous embodiment provides for D as a four atom linker asdescribed herein.

For formula II compounds, substituent X is selected from the groupconsisting of (C₃-C₁₄)-cycloalkylene and a (C₃-C₁₄)heterocycloalkylene.Variable M is selected from the group consisting of a bond,(C₁-C₆)alkylene-, —O—, —C(O)—, —C(S)—, —C(O)NH—, —C(S)NH—, —S—, —S(O)—,—S(O)₂—, —NR′—, and —C═NR¹¹—.

Substituent Y in Formula II is selected from the group consisting of H,(C₁-C₁₄)alkyl, —NR′R″, hydroxy(C₁-C₆)alkylene, (C₃-C₁₄)-cycloalkyl,(C₃-C₁₄)-cycloalkyl-(C₁-C₆)alkylene, (C₃-C₁₄)aryl,(C₃-C₁₄)aryl-(C₁-C₆)alkylene, (C₃-C₁₄)heterocycloalkyl,(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkylene, (C₃-C₁₄)heteroaryl,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene,(C₃-C₁₄)heteroaryl-(C₃-C₆)heterocycloalkylene-,(C₃-C₁₄)aryl-(C₃-C₁₄)heterocycloalkylene-,(C₃-C₁₄)-aryl-(C₁-C₆)alkyl-(C₃-C₁₄)heterocycloalkylene-,(C₃-C₁₄)heteroaryl-(C₁-C₆)alkyl-(C₃-C₁₄)heterocycloalkylene-, and(C₃-C₁₄)heterocycloalkyl-(C₁-C₆)alkyl-(C₃-C₁₄)heterocycloalkylene-.

For certain Formula II compounds, D is butylene, X is a(C₃-C₁₄)heterocycloalkylene, M is selected from the group consisting ofa bond, (C₁-C₆)alkylene-, —O—, —C(O)—, —C(S)—, —C(O)NH—, —C(S)NH—, —S—,—S(O)—, —S(O)₂—, —NR′—, and —C═NR¹¹— and Y is selected from the groupconsisting of (C₃-C₁₄)heteroaryl, (C₃-C₁₄)cycloalkyl, (C₃-C₁₄)aryl,(C₃-C₁₄)aryl-(C₁-C₆)alkylene and (C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene.According to another embodiment, however, M is selected from the groupconsisting of —C(O)—, —C(S)—, —C(O)NH—, —C(S)NH—, —S(O)₂— and —NR′—.

For certain Formula II compounds when M is —NR′—, substituent R′ can bea methylene group or an ethylene group. Alternatively, R′ is—C(O)—(C₁-C₈)alkylene, such as —C(O)-methylene.

Exemplary Formula II compounds include without limitation thoseillustrated in Table 1-A below. While some exemplary compounds aredepicted with stereochemistry, it should be understood that theinvention includes all possible stereoisomers, such as diastereomers, ofthe compounds.

TABLE 1-A Ex. Structure Name  1-A

2-amino-6-borono-2-(1-(5-(trifluoromethyl)pyridin-2-yl)piperidin-4-yl)hexanoic acid  2-A

2-amino-6-borono-2-(1-(4- (trifluoromethyl)pyrimidin-2-yl)piperidin-4-yl)hexanoic acid  3-A

2-amino-6-borono-2-(1-(2- (trifluoromethyl)quinolin-4-yl)piperidin-4-yl)hexanoic acid  4-A

2-amino-6-borono-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)hexanoic acid  5-A

2-amino-6-borono-2-(1-(5-fluoro-3,8- dimethylquinolin-2-yl)piperidin-4-yl)hexanoic acid  6-A

2-amino-6-borono-2-(1-(4- (trifluoromethyl)quinolin-2-yl)piperidin-4-yl)hexanoic acid  7-A

2-amino-6-borono-2-(1-(6-methyl-4-(trifluoromethyl)pyridin-2-yl)piperidin-4- yl)hexanoic acid  8-A

2-amino-6-borono-2-(1-(3,5-dichloropyridin-2- yl)piperidin-4-yl)hexanoicacid  9-A

2-amino-6-borono-2-(1-(4-((trifluoromethyl)pyridin-2-yl)piperidin-4-yl)hexanoic acid 10-A

2-amino-6-borono-2-(1-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)piperidin-4- yl)hexanoic acid 11-A

2-amino-6-borono-2-(1-(6-chlorobenzo[d]thiazol-2-yl)piperidin-4-yl)hexanoic acid 12-A

2-amino-6-borono-2-((S)-1-(4- chlorophenyl)pyrrolidin-3-yl)hexanoic acid13-A

2-amino-6-borono-2-((R)-1-(4- chlorophenyl)pyrrolidin-3-yl)hexanoic acid14-A

2-amino-6-borono-2-((R)-1-(4-chlorophenyl)-5-oxopyrrolidin-3-yl)hexanoic acid 15-A

(R)-2-amino-2-((1S,3R)-3-aminocyclopentyl)-6- boronohexanoic acid 16-A

(R)-2-amino-2-((1S,3S)-3-aminocyclopentyl)-6- boronohexanoic acid 17-A

(S)-2-amino-2-((1R,3S)-3-aminocyclopentyl)-6- boronohexanoic acid 18-A

2-amino-2-(azetidin-3-yl)-6-boronohexanoic acid 19-A

2-amino-6-borono-2-(morpholin-2-yl)hexanoic acid 20-A

2-amino-2-(4-aminocyclohexyl)-6- boronohexanoic acid 21-A

(S)-2-amino-6-borono-2-((1s,4R)-4-(4-chlorobenzylamino)cyclohexyl)hexanoic acid 22-A

(S)-2-amino-6-borono-2-((1r,4S)-4-(4-chlorobenzylamino)cyclohexyl)hexanoic acid 23-A

2-amino-6-borono-2-(1-cyclohexylpiperidin-4- yl)hexanoic acid 24-A

2-amino-6-borono-2-(1-cyclopentylpiperidin-4- yl)hexanoic acid 25-A

2-amino-6-borono-2-(1-(4,4- dimethylcyclohexyl)piperidin-4-yl)hexanoicacid 26-A

2-amino-6-borono-2-(1-(4-chlorobenzoyl)piperidin- 4-yl)hexanoic acid27-A

2-(1-acetylpiperidin-4-yl)-2-amino-6- boronohexanoic acid 28-A

2-amino-6-borono-2-(1-(2-(4-fluorophenyl)acetyl) piperidin-4-yl)hexanoicacid 29-A

2-amino-6-borono-2-(1-(2-(4- chlorophenyl)acetyl)piperidin-4-yl)hexanoicacid 30-A

2-amino-2-(1-benzoylpiperidin-4-yl)-6- boronohexanoic acid 31-A

2-amino-6-borono-2-(1-(4- chlorobenzylcarbamoyl)piperidin-4- yl)hexanoicacid 32-A

2-amino-6-borono-2-(1-(4- chlorophenylcarbamoyl)piperidin-4- yl)hexanoicacid 33-A

2-amino-6-borono-2-(1-(4- fluorophenethylcarbamoyl)piperidin-4-yl)hexanoic acid 34-A

2-amino-6-borono-2-(1-(4- chlorophenylcarbamothioyl)piperidin-4-yl)hexanoic acid 35-A

2-amino-6-borono-2-(1-(4- chlorophenylcarbamothioyl)pyrrolidin-3-yl)hexanoic acid 36-A

2-amino-6-borono-2-(1-(4- chlorophenylcarbamoyl)pyrrolidin-3-yl)hexanoic acid 37-A

2-amino-6-borono-2-((R)-1-(4- fluorobenzyl)pyrrolidin-3-yl)hexanoic acid38-A

2-amino-6-borono-2-((R)-1-(4- (trifluoromethyl)benzyl)pyrrolidin-3-yl)hexanoic acid 39-A

2-amino-6-borono-2-((R)-1-(4- methylbenzyl)pyrrolidin-3-yl)hexanoic acid40-A

2-amino-6-borono-2-(1-(2- nitrophenylsulfonyl)pyrrolidin-3- yl)hexanoicacid 41-A

2-amino-6-borono-2-(1-phenethylpiperidin-4- yl)hexanoic acid 42-A

2-amino-6-borono-2-(1-(3,4- dichlorophenylcarbamoyl)piperidin-4-yl)hexanoic acid 43-A

2-amino-6-borono-2-(1-(4- chlorobenzylcarbamothioyl)piperidin-4-yl)hexanoic acid 44-A

2-amino-6-borono-2-(1-(3-chloro-4-methylphenylcarbamothioyl)piperidin-4- yl)hexanoic acid 45-A

2-amino-6-borono-2-(1-(naphthalen-1-ylcarbamothioyl)piperidin-4-yl)hexanoic acid 46-A

2-amino-6-borono-2-(1-(3-(4-chlorophenyl)propyl) piperidin-4-yl)hexanoicacid 47-A

2-amino-6-borono-2-(1-(2,4- dichlorophenethyl)piperidin-4-yl)hexanoicacid 48-A

2-amino-6-borono-2-(1-(3,4- difluorobenzyl)piperidin-4-yl)hexanoic acid49-A

2-amino-6-borono-2-(1-(4-chloro-3- fluorobenzyl)piperidin-4-yl)hexanoicacid 50-A

2-amino-6-borono-2-(1-(3-(3-chloro-5-fluorophenyl)propyl)piperidin-4-yl)hexanoic acid 51-A

2-amino-6-borono-2-(1-((4-fluoronaphthalen-1-yl)methyl)piperidin-4-yl)hexanoic acid 52-A

2-amino-6-borono-2-(1-(3-(2,4- difluorophenyl)propyl)piperidin-4-yl)hexanoic acid 53-A

2-amino-6-borono-2-(1-(2-trifluoromethyl)benzyl) piperidin-4-yl)hexanoicacid 54-A

2-amino-6-borono-2-(1-(2- morpholinobenzyl)piperidin-4-yl)hexanoic acid55-A

2-amino-2-(1-(biphenyl-2-ylmethyl)piperidin-4- yl)-6-boronohexanoic acid56-A

2-amino-6-borono-2-(1-quinolin-8- ylmethyl)piperidin-4-yl)hexanoic acid57-A

2-amino-6-borono-2-(1-(2-(pyridin-3- yl)benzyl)piperidin-4-yl)hexanoicacid 58-A

2-amino-6-borono-2-(1-((3′-methoxybiphenyl-2-yl)methyl)piperidin-4-yl)hexanoic acid 59-A

2-amino-6-borono-2-(1-(3,4- difluorophenethyl)piperidin-4-yl)hexanoicacid 60-A

2-amino-6-borono-2-(1-(chroman-8- ylmethyl)piperidin-4-yl)hexanoic acid61-A

2-(1-((1H-indol-7-yl)methyl)piperidin-4-yl)-2- amino-6-boronohexanoicacid 62-A

2-amino-6-borono-2-(1-((1,3-dimethyl-1H-pyrazol-5-yl)methyl)piperidin-4-yl)hexanoic acid 63-A

2-amino-6-borono-2-(1-(3-(4- (trifluoromethyl)phenyl)propyl)piperidin-4-yl)hexanoic acid 64-A

2-amino-6-borono-2-(1-(4-(3,4- dichlorophenoxy)benzyl)piperidin-4-yl)hexanoic acid 65-A

2-(1-(3-((1H-pyrazol-1-yl)methyl)benzyl)piperidin-4-yl)-2-amino-6-boronohexanoic acid 66-A

2-amino-6-borono-2-(1-(3-(2,4- dichlorophenyl)propyl)piperidin-4-yl)hexanoic acid 67-A

2-amino-2-((R)-1-benzylpyrrolidin-3-yl)-6- boronohexanoic acid 68-A

2-amino-2-((S)-1-benzylpyrrolidin-3-yl)-6- boronohexanoic acid 69-A

2-amino-6-borono-2-((S)-1-(3,4- dichlorobenzyl)piperidin-3-yl)hexanoicacid 70-A

2-amino-2-(3-aminocyclobutyl)-6-boronohexanoic acid 71-A

(R)-2-amino-2-(1-benzylpiperidin-4-yl)-6- boronohexanoic acid 72-A

2-amino-2-(azepan-4-yl)-6-boronohexanoic acid 73-A

2-amino-6-borono-2-(1-(3,4-dichlorobenzyl)azepan- 4-yl) hexanoic acid74-A

cis-2-amino-2-(3-(benzylamino)cyclobutyl)-6- boronohexanoic acid 75-A

trans-2-amino-2-(3-(benzylamino)cyclobulyl)-6- boronohexanoic acid 76-A

Cis-2-amino-6-borono-2-(3-(4- (trifluoromethoxy)benzylamino)cyclobutyl)hexanoic acid 77-A

Cis 2-amino-2-(3-(biphenyl-4- ylmethylamino)cyclobutyl)-6-boronohexanoic acid 78-A

Cis-2-amino-6-borono-2-(3-((6- chlorobenzo[d][1,3]dioxol-5-yl)methylamino)cyclobutyl)hexanoic acid 79-A

Cis-2-amino-6-borono-2-(3-(quinolin-8- ylmethylamino)cyclobutyl)hexanoicacid 80-A

Cis-2-amino-6-borono-2-(3-(naphthalen-1-ylmethylamino)cyclobutyl)hexanoic acid 81-A

Cis-2-amino-2-(3-aminocyclobutyl)-6- boronohexanoic acid 82-A

Cis-2-amino-6-borono-2-(3-(4- chlorobenzylamino)cyclobutyl)hexanoic acid83-A

Cis-2-amino-6-borono-2-(3-(isobutylamino) cyclobutyl)hexanoic acid 84-A

2-amino-6-borono-2-(4-(4- chlorobenzoyl)cyclohexyl)hexanoic acid 85-A

2-amino-6-borono-2-(1-(5-chloropyridin-2- yl)piperidin-4-yl)hexanoicacid 86-A

2-amino-6-borono-2-(4-(4- chlorophenyl)cyclohexyl)hexanoic acid 87-A

2-amino-2-(1-benzylpiperidin-4-yl)-6- boronohexanoic acid 88-A

2-amino-6-borono-2-(piperidin-4-yl)hexanoic acid 89-A

2-amino-6-borono-2-(1-(4-chlorobenzyl)piperidin- 4-yl)hexanoic acid 90-A

2-amino-2-(1-(benzo[d][1,3]dioxol-5-ylmethyl)piperidin-4-yl)-6-boronohexanoic acid 91-A

2-amino-6-borono-2-(1-((6- chlorobenzo[d][1,3]dioxol-5-yl)methyl)piperidin-4-yl)hexanoic acid 92-A

2-amino-6-borono-2-(1-isopentylpiperidin-4- yl)hexanoic acid 93-A

2-amino-6-borono-2-(1-(4- (trifluoromethyl)benzyl)piperidin-4-yl)hexanoic acid 94-A

2-amino-6-borono-2-(1-(4-fluorobenzyl)piperidin-4- yl)hexanoic acid 95-A

2-amino-6-borono-2-(1-(3,4- dichlorobenzyl)piperidin-4-yl)hexanoic acid96-A

2-amino-6-borono-2-(1-(2-fluoro-4,5-dimethoxybenzyl)piperidin-4-yl)hexanoic acid 97-A

2-amino-6-borono-2-(1-(2,4- dichlorobenzyl)piperidin-4-yl)hexanoic acid98-A

2-amino-6-borono-2-(1-(naphthalen-1- ylmethyl)piperidin-4-yl)hexanoicacid 99-A

2-amino-6-borono-2-(1-(naphthalen-2- ylmethyl)piperidin-4-yl)hexanoicacid 100-A

2-amino-6-borono-2-(1-(4- (trifluoromethoxy)benzyl)piperidin-4-yl)hexanoic acid 101-A

2-amino-6-borono-2-(1-propylpiperidin-4- yl)hexanoic acid 102-A

2-amino-6-borono-2-(1-(3-phenylpropyl)piperidin- 4-yl)hexanoic acid103-A

2-amino-6-borono-2-(1-(3- (trifluoromethoxy)benzyl)piperidin-4-yl)hexanoic acid 104-A

2-amino-2-(1-(benzo[b]thiophen-3-ylmethyl)piperidin-4-yl)-6-boronohexanoic acid 105-A

3-((4-(1-amino-5-borono-1- carboxypentyl)piperidin-1- yl)methyl)benzoicacid 106-A

2-amino-6-borono-2-(1-(3-cyanobenzyl)piperidin-4- yl)hexanoic acidPharmaceutical Compositions and Dosages

The present invention is directed in part to pharmaceutical formulationsof Formula I or Formula II compounds and the use of the inentiveformulations to treat disease conditions associated with an imbalance ofarginase activity or the improper function of the arginase enzymes. Inone aspect, the present invention provides combination therapy in whicha patient or subject in need of therapy is administered a formulation ofa Formula I or Formula II compound in combination with one or more othercompounds having similar or different biological activities.

According to one aspect of the combination therapy routine, atherapeutically effective dose of a Formula I or Formula II compound maybe administered separately to a patient or subject in need thereof froma therapeutically effective dose of the combination drug. The person ofskill in the art will recognize that the two doses may be administeredwithin hours or days of each other or the two doses may be administeredtogether.

Exemplary disease conditions for which combination therapy in accordancewith the present invention may be administered include any of theconditions more specifically described hereinbelow. These includewithout limitation heart disease, hypertension, sexual disorders,gastric disorders, autoimmune disorders, parasitic infections, pulmonarydisorders, smooth muscle relaxation disorders and hemolytic disorders.

Suitable compounds that may be used in combination with a Formula I or aFormula II compound include without limitation:

-   -   Erectile Dysfunction: sildenafil, vardenafil, tadalafil and        alprostadil.    -   Pulmonary Hypertension/Hypertension: epoprostenol, iloprost,        bosentan, amlodipine, diltiazem, nifedipine, ambrisentan and        warfarin.    -   Asthma: fluticasone, budesonide, mometasone, flunisolide,        beclomethasone, montelukast, zafirlukast, zileuton, salmeterol,        formoterol, theophylline, albuterol, levalbuterol, pirbuterol,        ipratropium, prednisone, methylprednisolone, omalizumab,        corticosteroid and cromolyn.    -   Artherosclerosis: atorvastatin, lovastatin, simvastatin,        pravastatin, fluvastatin, rosuvastatin, gemfibrozil,        fenofibrate, nicotinic acid, clopidogrel.

The invention also provides a pharmaceutical composition comprising oneor more compounds according to Formula I or Formula II orpharmaceutically acceptable salts, solvates, stereoisomers, tautomers,or prodrugs, in admixture with a pharmaceutically acceptable carrier. Insome embodiments, the composition further contains, in accordance withaccepted practices of pharmaceutical compounding, one or more additionaltherapeutic agents, pharmaceutically acceptable excipients, diluents,adjuvants, stabilizers, emulsifiers, preservatives, colorants, buffers,or flavor imparting agents.

In one embodiment, the pharmaceutical composition comprises a compoundselected from those illustrated in Table 1 or Table 1-A, or apharmaceutically acceptable salt, solvate, stereoisomer, tautomer, orprodrug thereof, and a pharmaceutically acceptable carrier.

Suitable oral compositions in accordance with the invention includewithout limitation tablets, troches, lozenges, aqueous or oilysuspensions, dispersible powders or granules, emulsion, hard or softcapsules, syrups or elixirs.

Encompassed within the scope of the invention are pharmaceuticalcompositions suitable for single unit dosages that comprise a compoundof the invention, its pharmaceutically acceptable stereoisomer, prodrug,salt, solvate, hydrate, or tautomer and a pharmaceutically acceptablecarrier.

Inventive compositions suitable for oral use may be prepared accordingto any method known to the art for the manufacture of pharmaceuticalcompositions. For instance, liquid formulations of the inventivecompounds can contain one or more agents selected from the groupconsisting of sweetening agents, flavoring agents, coloring agents andpreserving agents in order to provide pharmaceutically elegant andpalatable preparations of the arginase inhibitor.

For tablet compositions of Formula I or Formula II compounds, the activeingredient in admixture with non-toxic pharmaceutically acceptableexcipients is used for the manufacture of tablets. Examples of suchexcipients include without limitation inert diluents, such as calciumcarbonate, sodium carbonate, lactose, calcium phosphate or sodiumphosphate; granulating and disintegrating agents, for example, cornstarch, or alginic acid; binding agents, for example starch, gelatin oracacia, and lubricating agents, for example magnesium stearate, stearicacid or talc. The tablets may be uncoated or they may be coated by knowncoating techniques to delay disintegration and absorption in thegastrointestinal tract and thereby to provide a sustained therapeuticaction over a desired time period. For example, a time delay materialsuch as glyceryl monostearate or glyceryl distearate may be employed.

Formulations for oral use may also be presented as hard gelatin capsuleswherein the active ingredient is mixed with an inert solid diluent, forexample, calcium carbonate, calcium phosphate or kaolin, or as softgelatin capsules wherein the active ingredient is mixed with water or anoil medium, for example peanut oil, liquid paraffin or olive oil.

For aqueous suspensions the inventive compound is admixed withexcipients suitable for maintaining a stable suspension. Examples ofsuch excipients include without limitation are sodiumcarboxymethylcellulose, methylcellulose, hydropropylmethylcellulose,sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia.

Oral suspensions can also contain dispersing or wetting agents, such asnaturally-occurring phosphatide, for example, lecithin, or condensationproducts of an alkylene oxide with fatty acids, for examplepolyoxyethylene stearate, or condensation products of ethylene oxidewith long chain aliphatic alcohols, for exampleheptadecaethyleneoxycetanol, or condensation products of ethylene oxidewith partial esters derived from fatty acids and a hexitol such aspolyoxyethylene sorbitol monooleate, or condensation products ofethylene oxide with partial esters derived from fatty acids and hexitolanhydrides, for example polyethylene sorbitan monooleate. The aqueoussuspensions may also contain one or more preservatives, for exampleethyl or n-propyl p-hydroxybenzoate, one or more coloring agents, one ormore flavoring agents, and one or more sweetening agents, such assucrose or saccharin.

Oily suspensions may be formulated by suspending the active ingredientsin a vegetable oil, for example arachis oil, olive oil, sesame oil orcoconut oil, or in a mineral oil such as liquid paraffin. The oilysuspensions may contain a thickening agent, for example beeswax, hardparaffin or cetyl alcohol.

Sweetening agents such as those set forth above, and flavoring agentsmay be added to provide palatable oral preparations. These compositionsmay be preserved by the addition of an anti-oxidant such as ascorbicacid.

Dispersible powders and granules suitable for preparation of an aqueoussuspension by the addition of water can provide the active ingredient inadmixture with a dispersing or wetting agent, suspending agent and oneor more preservatives. Suitable dispersing or wetting agents andsuspending agents are exemplified by those already mentioned above.Additional excipients, for example sweetening, flavoring and coloringagents, may also be present.

Pharmaceutical compositions of the invention may also be in the form ofoil-in-water emulsions. The oily phase may be a vegetable oil, forexample olive oil or arachis oil, or a mineral oil, for example liquidparaffin or mixtures of these. Suitable emulsifying agents may benaturally-occurring gums, for example gum acacia or gum tragacanthnaturally-occurring phosphatides, for example soy bean, lecithin, andesters or partial esters derived from fatty acids and hexitolanhydrides, for example sorbitan monooleate and condensation products ofthe said partial esters with ethylene oxide, for example polyoxyethylenesorbitan monooleate. The emulsions may also contain sweetening andflavoring agents.

Syrups and elixirs may be formulated with sweetening agents, for exampleglycerol, propylene glycol, sorbitol or sucrose. Such formulations mayalso contain a demulcent, a preservative, and flavoring and coloringagents. The pharmaceutical compositions may be in the form of a sterileinjectable, an aqueous suspension or an oleaginous suspension. Thissuspension may be formulated according to the known art using thosesuitable dispersing or wetting agents and suspending agents which havebeen mentioned above. The sterile injectable preparation may also besterile injectable solution or suspension in a non-toxic, parentallyacceptable diluent or solvent, for example as a solution in1,3-butanediol. Among the acceptable vehicles and solvents that may beemployed are water, Ringer's solution and isotonic sodium chloridesolution. In addition, sterile, fixed oils are conventionally employedas a solvent or suspending medium. For this purpose any bland fixed oilmay be employed including synthetic mono- or diglycerides. In addition,fatty acids such as oleic acid find use in the preparation ofinjectables.

Compounds that conform to Formula I or Formula II may also beadministered in the form of suppositories for rectal administration ofthe drug. These compositions can be prepared by mixing the drug with asuitable non-irritating excipient which is solid at ordinarytemperatures but liquid at the rectal temperature and will thereforemelt in the rectum to release the drug. Examples of such materials arecocoa butter and polyethylene glycols.

Compositions for parenteral administrations are administered in asterile medium. Depending on the vehicle used and the concentration ofthe drug in the formulation, the parenteral formulation can either be asuspension or a solution containing dissolved drug. Adjuvants such aslocal anesthetics, preservatives and buffering agents can also be addedto parenteral compositions.

Synthesis of Compounds

Compounds of the invention are prepared using any number of the generalmethodologies described hereinbelow and can be adapted to the synthesisof compounds not specifically described. The choice of an appropriatesynthetic methodology is guided by the choice of the Formula I orFormula II compound desired and the nature of functional groups presentin the intermediate and final product. Thus, selectiveprotection/deprotection protocols may be necessary during synthesisdepending on the specific functional groups desired and protectinggroups being used. A description of such protecting groups and how tointroduce and remove them is found in: Protective Groups in OrganicSynthesis, Third Edition, T. W. Green and P. G. M. Wuts, John Wiley andSons, New York, 1999. Illustrative of the general syntheticmethodologies used to make Formula I or Formula II compounds are thoseset forth below.

I. Synthesis of Formula I Compounds

Formula I compounds where D-B(OR³)(OR⁴) is —CH₂-L₁-L₂-CH₂—B(OH)₂ and R₂is a substituted alkyl group, can be conveniently prepared using aglycine benzophenone imine ester as illustrated in Scheme A set forthbelow. In this method the starting amino acid imine A-1 can be purchasedor prepared by reacting benzophenone imine with the desired amino acidester (O'Donnell, M. J., Aldrichimica Acta, 2001, 34, 3-15). Alkylationof A-1 in Scheme A with electrophile A-2 using typical alkylationconditions such as lithium bis(trimethylsilyl)amide, LDA or sodiumhydride in a polar aprotic solvent such as THF provides themonoalkylated product A-3. Similar reaction conditions can be used tointroduce the second substituent to provide intermediate A-4. Subsequenthydrolysis provides the target compound A-5 (Scheme A).

In some instances it may be preferable or necessary to build one or bothamino acid substituents in a multi-step process. An example of this isprovided in Scheme A where allyl bromide is used in the secondalkylation step giving intermediate A-6 under alkylating conditionsdescribed above. Following removal of the benzophenone and subsequentprotection of the amine, the terminal olefin is oxidized to givealdehyde intermediate A-8.

The highly versatile aldehyde group can be utilized to prepare a widevariety of target compounds. One convenient use is in reductiveamination reactions as shown in Scheme A. Here, treatment with thedesired amine and a reducing agent like sodium cyanoborohydride givesamine intermediate A-9, which after hydrolysis, provides the targetcompounds A-10. Depending on the specific functional group desired,certain protecting groups may be required.

Alternatively, in the case where a protected boronic acid electrophileis not available or is incompatible with synthetic protocol, Formula Icompounds can be synthesized by replacing electrophile A-2 with aterminal olefin followed by the introduction of boron in a later stepfollowing alkylation using hydroboration chemistry.

For enantioselective synthesis of Formula I compounds, a variety ofdifferent synthetic approaches may be used. Accordingly, in oneembodiment an optically pure ketone is used in place of the achiralbenzophenone. See, for example, Tabcheh, et al. Tetrahedron 1991, 47,4611-4618 and Belokon et al. Angew Chem, Int Ed 2001, 40, 1948-1951.

Alternatively, asymmetric induction can be achieved in the secondalkylation reaction by using a chiral catalyst. See, for example, Ooi,et al. Tet Lett. 2004, 45, 1675-1678; Ohshima et al. J. Am. Chem. Soc.2009, 125, 11206-11207; and, Belokon et al. Tetrahedron 2001, 57,2491-2498.

In yet another embodiment, enantioselectivity can be introduced by theuse of an optically pure oxazinone to synthesize Formula I compounds(Dastlik, K. A.; Sundermeier, U. Johns, D. M.; Chen, Y.; Williams, R. M.Synlett 2005, 4, 693-696). This approach is illustrated in Scheme B.

Here, the optically active oxazinone B-4 is used to stereo-selectivelydirect sequential alkylations to form intermediate B-7. Thesealkylations can be carried out under reaction conditions that arespecific for the electrophile being used (e.g. B-2, B-3, and B-6).Alternative approaches to synthesize B-5 and B-7 include the aldolreaction that involves the coupling of an aldehyde with the oxazinonefollowed by reduction of the resulting double bond. The inventivecompounds are obtained by decomposition of the di-substituted oxazinonefollowed by removal of the protecting groups. Thus, cleaving theoxazinone heterocycle via hydrogenation or using an alkali metal/ammoniareduction followed by treatment of intermediate B-8 with aqueous acidprovides the target disubstituted amino acid B-9.

If a butaneboronic acid is desired as one of the substituents in thefinal product electrophile, B-2 or B-3 can be used as an alkylatingagent. B-2 can be easily prepared from B-1 by treatment with pinacol inTHF. If iodo-intermediate B-3 is desired, it can be prepared from thecorresponding bromide via treatment with sodium iodide in acetone.

Alternatively, synthesis entails modification of one or bothsubstituents after the alkylation steps. This may be required when thedesired functionality in the final product is not compatible with thealkylation reaction conditions or if the desired substituent is notconveniently introduced as an electrophile due to limited reactivity. Anexample is illustrated in Scheme C, wherein allyl iodide is used as anefficient alkylating agent then further modified after cleavage of theoxazinone ring system. In this example, the allyl intermediate C-1 istreated with lithium in ammonia to remove the oxazinone ring. Theresulting acid can be protected as ester C-3 and subsequently treatedwith ozone to give the corresponding aldehyde.

The aldehyde (C-4) is a very flexible functional group and can be usedin many types of reactions to make a wide variety of different analogs.As an example, it can be used in reductive amination reactions toprepare compounds with amine substituents R1 and R2 as in intermediateC-5. The final target compounds (C-6) can be obtained after deprotectionof the ester, amino and boronic acid moieties.

In another embodiment, syntheses of some Formula I compounds employ theUgi reaction (Doemling, A., Chem. Rev. 2006, 106, 17-89. This method isillustrated in Scheme D. In the Ugi reaction a ketone or aldehyde (D-3)is treated with an isocyanate such as tert-butyl isocyanate and an aminesource like ammonium acetate to give directly the amino acid derivativewith the carboxylic acid and amine protected as a tert-butylamide andacetamide respectively. In this reaction different isocyanates and aminesources can be used depending on the desired amine and carboxylic acidprotecting groups desired. If optically active products are desiredchiral optically pure isocyanates and/or amine sources can be used. Thereactions using these reagents may be enantioselective, or at leastprovide diastereomeric mixtures of products that can be easilyseparated.

The synthesis of key intermediate D-3 can be completed using a widevariety of methods. One very convenient method utilizes carboxylic acidD-1. In this method the carboxylic acid is activated and coupled withmethoxymethylamine to form Weinreb amide D-2. This can be completedusing a wide variety of coupling regents such as EDC, DCC or PyBOP, ordirectly from the acid chloride of D-1. The Weinreb amide can beconverted to the desired ketone by reacting it with the appropriateGrignard reagent to give intermediate D-3.

After the Ugi reaction is complete, the terminal olefin can be treatedwith a borane source such as pinacolborane to introduce the boronic acidmoiety. Final deprotection of intermediate D-5 gives target compoundD-6.

Many examples with an aminomethylene substituent in the α-position canbe conveniently prepared using the method illustrated in Scheme E. Herean aminomalonate starting material such as E-1, where the amine isprotected as a benzyl carbamate (Cbz) and the acids are protected asesters, is used to generate disubstituted amino acid derivative E-2 viaalkylation with 4-bromobutene. Selective hydrolysis of the diester withpotassium hydroxide in ethanol gives acid ester E-3. Selective reductionof the carboxylic acid using a chloroformate and sodium borohydridegives alcohol E-4 which can be protected using dimethoxypropane and anorganic acid such as toluenesulfonic acid. Hydrboration of E-5 withpinacolborane gives E-6, which after deprotection provides alcohol E-7.Oxidation of the alcohol provides the intermediate aldehyde E-8, whichafter reductive amination and final deprotection gives the targetcompound E-11.

As an alternative to the method in Scheme E where the benzyl carbamateis used as the amine protecting group, the corresponding t-butylcarbamate (Boc) protected amino malonate derivative can also be used.Here, as illustrated in Scheme F, diethyl2-(tert-butoxycarbonylamino)malonate F-1 is alkylated with 4-bromobuteneto give the disubstituted malonate intermediate F-2. Selectivehydrolysis of the diester using basic conditions such as potassiumhydroxide in ethanol gives mono acid F-3. Reduction of the carboxylicacid using ethyl chloroformate and sodium borohydride gives the primaryalcohol which can be conveniently protected as an acetate using standardconditions such as acetic anhydride and DMAP. If desired, manyalternative protecting groups can be used. This group is simplyintroduced to facilitate the subsequent hydroboration reaction thatprovides intermediate F-6. Once the hydroboration reaction is complete,the acetate can be removed and the resulting alcohol (F-7) can beoxidized to the corresponding aldehyde (F-8) and used in reductiveamination reactions with amine F-9 to give protected products F-10.Deprotection using aqueous acid then gives the desired products F-11. Inaddition to reductive amination reactions, intermediate aldehyde F-8 canbe used in a wide variety of reactions to produce desired substituents.The use of aldehydes to form heterocycles or other products is wellknown to those skilled in the art of organic synthesis.

Those having skill in the art will recognize that the starting materialsand reaction conditions may be varied, the sequence of the reactionsaltered, and additional steps employed to produce compounds encompassedby the present invention, as demonstrated by the following examples. Insome cases, protection of certain reactive functionalities may benecessary to achieve some of the above transformations. In general, theneed for such protecting groups as well as the conditions necessary toattach and remove such groups will be apparent to those skilled in theart of organic synthesis.

The preparation of Formula I compounds of the present invention isillustrated further by the following examples, which are not to beconstrued as limiting the invention in scope or spirit to the specificprocedures and compounds described in them.

EXEMPLARY FORMULA I COMPOUNDS Example 1: Preparation of(R)-2-amino-6-borono-2-(2-((S)-3-(hydroxymethyl)-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)hexanoicacid dihydrochloride

Step 1: 2-(4-bromobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

After gently warming until melted, 4-bromo-1-butylboronic acid catecholester (112.2 g, 0.44 mol, 1.0 equiv), while under a stream of nitrogen,was added to a 3-necked 500 mL round-bottomed flask, diluted withfreshly distilled THF (150 mL, 3.0 M) and treated with pinacol (104.0 g,0.88 mol, 2 equiv) in one portion. After stirring for 16 h under anitrogen atmosphere the resulting solution was concentrated. The crudeproduct was diluted with heptane (500 mL) and cooled in an ice-waterbath. After 1 h, the precipitated catechol was removed by filtration andthe remaining solution was filtered through a short pad of silica gel(500 g) wetted with heptane. After eluting with solutions of 5% ethylacetate in heptane (700 mL) and 10% ethyl acetate in heptane (700 mL),the filtrate was concentrated to give2-(4-bromobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as a colorlessoil (112.7 g, 97%). ¹H NMR (CDCl₃, 300 MHz) δ 3.38 (t, J=6.6 Hz, 2H),1.90-1.78 (m, 2H), 1.58-1.44 (m, 2H), 1.26 (s, 12H), 0.78 (t, J=7.5 Hz,2H); ESI-LCMS m/z calcd for C₁₀H₂₀BBrO₂: expected 262.1. found 263.1(M+H)⁺.

Step 2: 2-(4-iodobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

While under a nitrogen atmosphere, a solution of2-(4-bromobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (46.2 g, 0.176mol, 1.0 equiv) and sodium iodide (52.8 g, 0.35 mol, 2 equiv) in acetone(176 mL, 1.0 M) was heated to 50° C. for 4 h. After cooling to roomtemperature the solution was concentrated under reduced pressure. Theresulting residue was diluted with heptane (200 mL) and filtered througha short pad of silica gel (300 g) wetted with heptane. After elutingwith a solution of 10% ethyl acetate in heptane (500 mL) the filtratewas concentrated to give2-(4-iodobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as a colorlessoil (53.5 g, 98%). ¹H NMR (CDCl₃, 300 MHz) δ 3.18 (t, J=7.2 Hz, 2H),1.90-1.78 (m, 2H), 1.58-1.44 (m, 2H), 1.24 (s, 12H), 0.79 (t, J=7.5 Hz,2H); ESI-LCMS m/z calcd for C₁₀H₂₀BIO₂: expected 310.1. found 311.1(M+H)⁺.

Step 3: (3R,5R,6S)-tert-butyl2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylate

A solution of (2S,3R)-tert-butyl6-oxo-2,3-diphenylmorpholine-4-carboxylate (4.69 g, 13.27 mmol) and2-(4-iodobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (d 1.38, 5.96mL, 8.23 g, 26.5 mmol, 2 equiv) in THF (66 mL, 0.2 M) and HMPA (6.6 mL)was cooled to −78° C. and treated with sodium bis(trimethylsilyl)amide(14.6 mL, 1.0 M, 1.1 equiv) drop wise over 5 min and stirred for 1 h.After warming to room temperature and stirring for an additional 2 h,the solution was cooled to 0° C. and quenched with 0.5 NHC (2-3 equiv).The resulting solution was diluted with heptane and washed successivelywith water and saturated aqueous NaCl, dried over MgSO₄, filtered andconcentrated. Purification by MPLC (1-60% ethyl acetate in heptane over6 CV) gave (3R,5R,6S)-tert-butyl2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylateas a white solid (6.66 g, 94%); ESI-LCMS m/z calcd for C₃₁H₄₂BNO₂:expected 535.3. found 536.4 (M+H)⁺.

Step 4: (3R,5R,6S)-tert-butyl3-allyl-2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylate

A solution of (3R,5R,6S)-tert-butyl2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylate(5.00 g, 9.34 mmol) and TMEDA (10 mL, 65 mmol, 7 equiv) in THF (51 mL,0.2 M) was cooled to −78° C. and treated with allyl iodide (17 mL, 187mmol, 20 equiv) and potassium bis(trimethylsilyl)amide (47 mL, 0.9 M inTHF, 46.7 mmol, 5 equiv) drop wise and stirred for 30 min. Once theaddition was complete, the cooling bath was removed and the mixture wasstirred over night. Once complete by TLC, the reaction mixture wasquenched with 0.5 N HCl (5-10 equiv), diluted with heptane and washedsuccessively with water and saturated aqueous NaCl, dried over MgSO₄,filtered and concentrated. Purification by MPLC (1-60% ethyl acetate inheptane over 6 CV) gave (3R,5R,6S)-tert-butyl3-allyl-2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylateas colorless oil (5.2 g, 96%). R_(f) 0.55 (30% ethyl acetate inheptane); ¹H NMR (CDCl₃, 300 MHz) δ 7.39-7.14 (m, 10H), 7.10 (dd, J₁=5.4Hz, J₂=1.8 Hz, 1H), 6.08 (d, J=5.4 Hz, 1H), 5.95-5.80 (m, 1H), 5.27-5.17(m, 2H), 3.30-3.15 (m, 1H), 2.89-2.76 (m, 1H), 2.20-2.07 (m, 2H), 1.54(s, 9H), 1.35-1.21 (m, 4H), 1.78 (s, 12H), 0.46 (t, J=8.4 Hz, 2H);ESI-LCMS m/z calcd for C₃₄H₄₆BNO₆: expected 575.3. found 574.3 (M+H)⁺.

Step 5: (R)-methyl2-allyl-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A three-necked RBF equipped with nitrogen inlet tube and dry icecondenser was charged with (3R,5R,6S)-tert-butyl3-allyl-2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylate(4.60 g, 8.00 mmol) and THF (10 mL). After cooling the condenser to −78°C. and the flask to −45° C. (CO₂ (s), CH₃CN), ammonia (80 mL) wascondensed into the flask. Once complete, lithium metal (0.55 g, 80 mmol,small pieces) was carefully added over 10 min. After stirring anadditional 40 min, the reaction mixture was carefully quenched withNH₄Cl(s) until the solution became clear. The bath was removed and theammonia was allowed to evaporate over night. The resulting residue wasdiluted with ethyl acetate and washed successively with 0.5 N HCl andsaturated aqueous NaCl, dried over MgSO₄, filtered and concentrated. Thecrude product was dissolved in 50% methanol in toluene (80 mL, 0.1 M)and treated with TMSCHN₂ (2.0 M in hexanes) until the pale yellow colorpersisted. With TLC indicating the reaction complete, the excess TMSCHN₂was quenched with acetic acid until the solution became clear. Thesolution was concentrated, diluted with ethyl acetate and washedsuccessively with saturated aqueous NaHCO₃ and saturated aqueous NaCl,dried over MgSO₄, filtered and concentrated. Purification by MPLC (1-60%ethyl acetate in heptane over 6 CV) gave (R)-methyl2-allyl-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas colorless oil (1.9 g, 58%). R_(f) 0.46 (30% ethyl acetate inheptane); ¹H NMR (CDCl₃, 300 MHz) δ 5.70-5.52 (m, 1H), 5.49-5.36 (m,1H), 5.05 (dd, J₁=13.8 Hz, J₂=1.2 Hz, 1H), 3.73 (s, 3H), 3.09-2.96 (m,1H), 2.50 (dd, J₁=13.8 Hz, J₂=7.8 Hz, 1H), 2.29-2.10 (m, 1H), 1.78-1.65(m, 1H), 1.43 (s, 9H), 1.42-1.26 (m, 4H), 1.23 (s, 12H), 0.74 (t, J=7.5Hz, 2H); ESI-LCMS m/z calcd for C₂₁H₃₈BNO₆: expected 411.3. found 412.3(M+H)⁺.

Step 6: (R)-methyl2-(tert-butoxycarbonylamino)-2-(2-oxoethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of (R)-methyl2-allyl-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(1.90 g, 4.62 mmol) in dichloromethane (90 mL, 0.05 M) was cooled to−78° C. and treated with ozone until a pale blue-gray color appeared.After TLC indicated the absence of starting material, the ozone inlettube was replaced with nitrogen and nitrogen was bubbled through thesolution for 20 min to remove any excess ozone. Triphenylphosphine (3.6g, 13.8 mmol, 3 equiv) was added in one portion, the cooling bath wasremoved and the mixture was stirred for 4 h. The solution wasconcentrated and purified by MPLC (1-50% ethyl acetate in heptane over 6CV) and gave (R)-methyl2-(tert-butoxycarbonylamino)-2-(2-oxoethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas a colorless oil (1.28 g, 67%). R_(f) 0.55 (30% ethyl acetate inheptane); ¹H NMR (CDCl₃, 300 MHz) δ 9.66 (s, 1H), 5.62 (br s, 1H), 3.75(s, 3H), 3.60 (br d, J=17.4 Hz, 1H), 2.95 (d, J=17.4 Hz, 1H), 2.30-2.15(m, 1H), 1.70-1.54 (m, 1H), 1.40 (s, 9H), 1.39-1.24 (m, 4H), 0.74 (t,J=7.8 Hz, 2H); ESI-LCMS m/z calcd for C₂₀H₃₆BNO₇: expected 413.3. found414.3 (M+H)⁺.

Step 7: (R)-methyl2-(tert-butoxycarbonylamino)-2-(2-((S)-3-(hydroxymethyl)-3,4-dihydroisoquinolin-2(1H-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of (R)-methyl2-(tert-butoxycarbonylamino)-2-(2-oxoethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(0.148 g, 0.358 mmol, 1.0 equiv.) and(S)-(1,2,3,4-tetrahydroisoquinolin-3-yl)methanol (0.088 g, 0.54 mmol,1.5 equiv.) in 1,2-dichloroethane (0.34 mL, 0.5 M) was treated withsodium triacetoxyborohydride (0.19 g, 0.90 mmol, 2.5 equiv) in oneportion. After stirring for 1.5 h, the reaction mixture was quenchedwith saturated aqueous NaHCO₃ (1 mL) and stirred for an additional 5min. The resulting mixture was added to a separatory funnel, dilutedwith saturated aqueous NaCl (5 mL) and extracted with dichloromethane(2×10 mL). The organic layer was dried over MgSO₄, filtered andconcentration under reduced pressure. Purification by flash columnchromatography eluting with 5% methanol in chloroform gave (R)-methyl2-(tert-butoxycarbonylamino)-2-(2-((S)-3-(hydroxymethyl)-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas a pale yellow oil (0.187 g, 93%). R_(f) 0.52 (10% methanol indichloromethane); ¹H NMR (CDCl₃, 300 MHz) δ 7.15-7.08 (m, 2H), 7.07-6.98(m, 2H), 5.90 (s, 1H), 3.78 (d, J=16.2 Hz, 1H), 3.70 (s, 3H), 3.60-3.47(m, 2H), 3.04-2.93 (m, 1H), 2.92-2.82 (m, 1H), 2.71-2.60 (m, 1H),2.56-2.38 (m, 2H), 2.37-2.23 (m, 1H), 2.21-2.10 (m, 1H), 1.77-1.63 (m,1H), 1.42 (s, 9H), 1.43-1.26 (m, 3H), 1.23 (s, 12H), 1.22-1.16 (m, 1H),0.99-0.82 (m, 2H), 0.74 (t, J=7.5 Hz, 2H); ESI-LCMS m/z calcd forC₃₀H₄₉BN₂O₇: expected 560.4. found 561.4 (M+H)⁺.

Step 8:(R)-2-amino-6-borono-2-(2-((S)-3-(hydroxymethyl)-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)hexanoicacid dihydrochloride

A solution of (R)-methyl2-(tert-butoxycarbonylamino)-2-(2-((S)-3-(hydroxymethyl)-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(0.187 g, 0.334 mmol) in 6 N HCl (5 mL) was heated to a gentle refluxfor 16 h. After cooling to room temperature, the reaction mixture wastransferred to a separatory funnel, diluted with deionized water (5 mL)and washed with dichloromethane (3×5 mL). The aqueous layer was frozenin liquid nitrogen and lyophilized to give(R)-2-amino-6-borono-2-(2-((S)-3-(hydroxymethyl)-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)hexanoicacid dihydrochloride as an off-white foam (0.122 g, 89%). ¹H NMR (D₂O,300 MHz) δ 7.26-7.08 (m, 4H), 3.89-375 (m, 1H), 3.78-3.65 (m, 1H),3.61-3.50 (m, 1H), 3.41-3.18 (m, 1H), 3.10-3.00 (m, 1H), 2.99-2.75 (m,2H), 2.35-2.20 (m, 2H), 1.84-1.60 (m, 2H), 1.31-1.16 (m, 2H), 1.15-1.00(m, 2H), 0.66-0.50 (m, 2H); ESI-LCMS m/z calcd for C₁₈H₂₉BN₂O₅: expected364.2. found 365.2 (M+H)⁺.

Example 2: Preparation of(R)-2-amino-6-borono-2-(2-((S)-2-(methoxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride

(R)-2-Amino-6-borono-2-(2-((S)-2-(methoxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 1, except (S)-2-(methoxymethyl)pyrrolidine is used as theamine in step 7. ¹H NMR (D₂O, 300 MHz) δ 3.68-3.50 (m, 3H), 3.50-3.39(m, 1H), 3.38-3.10 (m, 2H), 3.24 (s, 3H), 3.10-2.96 (m, 1H), 2.22-2.10(m, 2H), 2.10-2.01 (m, 1H), 2.01-1.89 (m, 1H), 1.88-1.62 (m, 4H),1.35-1.16 (m, 3H), 1.16-1.00 (m, 1H), 0.63 (t, J=7.8 Hz, 2H); ESI-LCMSm/z calcd for C₁₄H₂₉BN₂O₅: expected 316.2. found 317.2 (M+H)⁺.

Example 3: Preparation of(R)-2-amino-6-borono-2-(2-((R)-2-(methoxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride

(R)-2-Amino-6-borono-2-(2-((R)-2-(methoxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 1, except (R)-2-(methoxymethyl)pyrrolidine is used as theamine in step 7. ¹H NMR (D₂O, 300 MHz) δ 3.67-3.35 (m, 4H), 3.23 (s,3H), 3.08-2.91 (m, 3H), 2.25-1.55 (m, 8H), 1.36-1.16 (m, 3H), 1.16-1.00(m, 1H), 0.63 (br s, 2H); ESI-LCMS m/z calcd for C₁₄H₂₉BN₂O₅: expected316.2. found 317.2 (M+H)⁺.

Example 4: Preparation of(R)-2-amino-6-borono-2-(2-(4-hydroxypiperidin-1-yl)ethyl)hexanoic aciddihydrochloride

(R)-2-Amino-6-borono-2-(2-(4-hydroxypiperidin-1-yl)ethyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 1, except piperidin-4-ol is used as the amine in step 7. ¹H NMR(D₂O, 300 MHz) δ 4.05-3.96 (m, 1H), 3.82-3.68 (m, 1H), 3.51-3.49 (m,1H), 3.33-3.05 (m, 2H), 3.05-2.81 (m, 2H), 2.17-1.98 (m, 3H), 1.87-1.44(m, 5H), 1.30-1.15 (m, 3H), 1.12-0.99 (m, 1H), 0.62 (t, J=7.8 Hz, 2H);ESI-LCMS m/z calcd for C₁₃H₂₇BN₂O₅: 302.2. found 303.2 (M+H)⁺.

Example 5: Preparation of(R)-2-amino-6-borono-2-(2-((S)-3-hydroxypiperidin-1-yl)ethyl)hexanoicacid dihydrochloride

(R)-2-Amino-6-borono-2-(2-((S)-3-hydroxypiperidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 1, except (S)-piperidin-3-ol is used as the amine in step 7.¹H NMR (D₂O, 300 MHz) δ 4.16-4.04 (m, 1H), 3.48-3.12 (m, 4H), 3.07-2.90(m, 1H), 2.88-2.70 (m, 1H), 2.25-2.00 (m, 2H), 2.00-1.80 (m, 1H),1.80-1.45 (m, 5H), 1.32-1.14 (m, 3H), 1.14-1.00 (m, 1H), 0.63 (t, J=7.8Hz, 2H); ESI-LCMS m/z calcd for C₁₃H₂₇BN₂O₅: 302.2. found 303.2 (M+H)⁺.

Example 6: Preparation of(R)-2-amino-6-borono-2-(2-((3,4-dimethoxyphenethyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride

(R)-2-Amino-6-borono-2-(2-((3,4-dimethoxyphenethyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 1, except 2-(3,4-dimethoxyphenyl)-N-methylethanamine is usedas the amine in step 7. ¹H NMR (D₂O, 300 MHz) δ 6.83-6.59 (m, 3H), 3.68(s, 3H), 3.66 (s, 3H), 3.40-2.99 (m, 4H), 2.97-2.79 (m, 2H), 2.75 (s,3H), 2.20-2.01 (m, 2H), 1.81-1.47 (m, 2H), 1.33-1.08 (3H), 1.07-0.96 (m,1H), 0.61 (t, J=6.9 Hz, 2H); ESI-LCMS m/z calcd for C₁₉H₃₃BN₂O₆: 396.2.found 397.2 (M+H)⁺.

Example 7: Preparation of(R)-2-amino-6-borono-2-(2-((R)-3-(hydroxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride

(R)-2-Amino-6-borono-2-(2-((R)-3-(hydroxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 1, except (R)-pyrrolidin-3-ylmethanol is used as the amine instep 7. ¹H NMR (D₂O, 300 MHz) δ 3.70-3.18 (m, 5H), 3.16-2.88 (m, 3H),2.11-1.85 (m, 3H), 1.82-1.51 (3H), 1.30-1.14 m, 3H), 1.11-0.99 (m, 1H),0.62 (t, J=7.8 Hz, 2H); ESI-LCMS m/z calcd for C₁₃H₂₇BN₂O₅: 302.2. found303.3 (M+1)⁺.

Example 8: Preparation of(R)-2-amino-6-borono-2-(2-thiomorpholinoethyl)hexanoic aciddihydrochloride

(R)-2-Amino-6-borono-2-(2-thiomorpholinoethyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 1, except thiomorpholine is used as the amine in step 7. ¹H NMR(D₂O, 300 MHz) δ 3.61-3.57 (m, 2H), 3.30-3.17 (m, 1H), 3.16-2.99 (m,3H), 2.98-2.80 (m, 2H), 2.73-2.60 (m, 2H), 2.29-2.14 (m, 2H), 1.90-1.61(m, 2H), 1.30-1.15 (m, 3H), 1.12-0.95 (m, 1H), 0.78 (t, J=7.2 Hz, 2H);ESI-LCMS m/z calcd for C₁₂H₂₅BN₂O₄S: 304.2. found 305.2 (M+1)⁺.

Example 9: Preparation of(R)-2-amino-6-borono-2-(2-(4-(2-hydroxyethyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride

(R)-2-Amino-6-borono-2-(2-(4-(2-hydroxyethyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 1, except 2-(piperidin-4-yl)ethanol is used as the amine instep 7. ¹H NMR (D₂O, 300 MHz) δ 3.51-3.30 (m, 3H), 3.30-3.02 (m, 2H),3.01-2.89 (m, 1H), 2.88-2.60 (m, 2H), 2.20-1.95 (m, 2H), 1.90-1.63 (m,6H), 1.64-1.40 (m, 1H), 1.40-1.28 (m, 2H), 1.28-1.10 (m, 3H), 1.11-0.93(m, 1H), 0.61 (t, J=7.5 Hz, 2H); ESI-LCMS m/z calcd for C₁₅H₃₁BN₂O₅:330.2. found 331.3 (M+1)⁺.

Example 10: Preparation of(R)-2-amino-6-borono-2-(2-((S)-2-(hydroxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid

(R)-2-Amino-6-borono-2-(2-((S)-2-(hydroxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid is prepared in a manner analogous to that set forth in Example 1,except (S)-pyrrolidin-2-ylmethanol is used as the amine in step 7. ¹HNMR (D₂O, 400 MHz) δ 3.85-3.75 (m, 1H), 3.72-3.63 (m, 1H), 3.60-3.45 (m,2H), 3.34-3.12 (m, 2H), 3.10-3.00 (m, 1H), 2.22-2.07 (m, 3H), 2.10-1.75(m, 5H), 1.87 (s, 3H), 1.45-1.30 (m, 3H), 1.28-1.10 (m, 1H), 0.72 (t,J=7.5 Hz, 2H). ESI⁺ MS: obsd m/z 267.1 (M−36+H)⁺.

Example 11: Preparation of(R)-2-amino-6-borono-2-(2-(methyl(phenethyl)amino)ethyl) hexanoic aciddihydrochloride

(R)-2-Amino-6-borono-2-(2-(methyl(phenethyl)amino)ethyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 1, except N-methyl-2-phenylethanamine is used as the amine instep 7. ¹H NMR (D₂O, 400 MHz) δ 7.45-7.38 (m, 2H), 7.37-7.31 (m, 3H),3.51-3.36 (m, 3H), 3.25-3.13 (m, 1H), 3.09 (t, J=7.8 Hz, 2H), 2.92 (s,3H), 2.26-2.16 (m, 2H), 1.88-1.70 (m, 2H), 1.45-1.33 (m, 2H), 1.26-1.12(m, 2H), 0.78 (t, J=7.6 Hz, 2H). ESI⁺ MS: obsd m/z 319.1 (M−18+H)⁺,301.1 (M−36+H)⁺.

Example 12: Preparation of(R)-2-amino-6-borono-2-(2-(((S)-2-hydroxy-2-(3-hydroxyphenyl)ethyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride

(R)-2-Amino-6-borono-2-(2-(((S)-2-hydroxy-2-(3-hydroxyphenyl)ethyl)(methyl)amino)ethyl)hexanoicacid is prepared in a manner analogous to that set forth in Example 1,except (S)-3-(1-hydroxy-2-(methylamino)ethyl)phenol is used as the aminein step 7. ¹H NMR (D₂O, 400 MHz) δ 7.33 (t, J=7.8 Hz, 1H), 7.02-6.86 (m,3H), 5.14-5.08 (m, 1H), 3.52-3.23 (m, 3H), 2.97 (s, 3H), 2.40-2.28 (m,1H), 2.27-2.15 (m, 1H), 1.87-1.70 (m, 2H), 1.46-1.32 (m, 3H), 1.30-1.15(m, 2H), 0.78 (t, J=7.6 Hz, 2H). ESI⁺ MS: obsd m/z 333.1 (M−36+H)⁺,315.1 (M−54+H)⁺.

Example 13: Preparation of(R)-2-Amino-6-borono-2-[2-piperidin-1-yl)-ethyl]-hexanoic aciddihydrochloride

(R)-2-Amino-6-borono-2-[2-piperidin-1-yl)-ethyl]-hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 1, except piperidinyl is used as the amine in step 7. The finalstep is as follows: a solution of(R)-2-tert-butoxycarbonylamino-2-(2-piperidin-1-yl-ethyl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid methyl ester (182 mg) in 6 N hydrochloric acid (5 mL) was stirredat 95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give(R)-2-amino-6-borono-2-[2-piperidin-1-yl)-ethyl]-hexanoic aciddihydrochloride as a colorless foam (72 mg, 53%); ¹H NMR (D₂O, 300 MHz)δ 3.34 (d, J=11.5 Hz, 2H), 3.14 (m, 1H), 2.97 (m, 1H), 2.77 (t, J=12 Hz,2H), 2.19 (t, J=8.5 Hz, 2H), 1.76 (m, 4H), 1.55 (m, 3H), 1.23 (m, 4H),1.06 (m, 1H) and 0.59 (t, J=7.5 Hz, 2H).

Example 14: Preparation of (R)-2-amino-2-[4-borono-butyl)]-pent-4-enoicacid hydrochloride

(R)-2-amino-2-[4-borono-butyl)]-pent-4-enoic acid hydrochloride isprepared in a manner analogous to that set forth in Example 1, exceptstep 6 and 7 are not done. The final step is as follows: a solution of(R)-2-tert-butoxycarbonylamino-2-[4-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-butyl]-pent-4-enoicacid (85 mg) in 6 N hydrochloric acid (4 mL) was stirred at 65° C.overnight. After cooling to room temperature, the reaction mixture wastransferred to a separatory funnel, diluted with deionized water (5 mL)and washed with dichloromethane (3×). The aqueous layer was frozen inliquid nitrogen and lyophilized to give(R)-2-amino-2-[4-borono-butyl)]-pent-4-enoic acid hydrochloride as acolorless foam (48 mg, 89%); ¹H NMR (D₂O, 300 MHz) δ 5.60 (m, 1H), 5.16(m, 2H), 2.60 (m, 1H), 2.45 (m, 1H), 1.78 (m, 2H), 1.26 (m, 3H), 1.09(m, 1H) and 0.63 (t, J=7.5 Hz, 2H); ESI-LCMS m/z calcd for C₉H₁₈BNO₄:215.1. found 216.1 (M+1)⁺.

Example 15: Preparation of (S)-2-amino-6-borono-2-ethylhexanoic acidhydrochloride Step 1: (3S,5R,6S)-tert-butyl3-ethyl-2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylate

A solution of (3R,5R,6S)-tert-butyl2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylate(1.00 g, 1.87 mmol) and TMEDA (2 mL, 13 mmol, 7 equiv) in1,2-dimethoxyethane (9.4 mL, 0.2 M) was cooled to −78° C. and treatedwith ethyl iodide (3 mL, 37 mmol, 20 equiv) and potassiumbis(trimethylsilyl)amide (9.4 mL, 0.9 M in THF, 9.4 mmol, 5 equiv) dropwise. After stirring for an additional 30 min at −78° C., the coolingbath was removed and the mixture was stirred over night. The reactionwas incomplete by TLC and therefore was recooled to −78° C. and treatedwith additional potassium bis(trimethylsilyl)amide (9.4 mL, 0.9 M inTHF, 9.4 mmol, 5 equiv) and ethyl iodide (3 mL, 37 mmol, 20 equiv).After the additions were complete, the bath was removed and the solutionwas stirred overnight. Once complete by TLC, the reaction mixture wasquenched with 0.5 N HCl (5-10 equiv), diluted with heptane and washedsuccessively with water and saturated aqueous NaCl, dried over MgSO₄,filtered and concentrated. Purification by MPLC (1-60% ethyl acetate inheptane over 6 CV) gave (3S,5R,6S)-tert-butyl3-ethyl-2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylateas colorless oil (0.68 g, 65%). R_(f) 0.40 (30% ethyl acetate inheptane); ¹H NMR (CDCl₃, 300 MHz) δ 7.31-7.15 (m, 10H), 7.08 (d, J=2.4Hz, 1H), 6.02 (d, J=2.4 Hz, 1H), 2.35-2.22 (m, 2H), 2.22-2.07 (m, 2H),1.47 (s, 9H), 1.26-1.21 (m, 4H), 1.15 (s, 12H), 1.00 (t, J=7.5 Hz, 3H),0.85 (t, J=6.8 Hz, 2H); ESI-LCMS m/z calcd for C₃₃H₄₆BNO₆: 563.3. found564.3 (M+1)⁺.

Step 2: (S)-methyl2-(tert-butoxycarbonylamino)-2-ethyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A three-necked round-bottomed flask equipped with nitrogen inlet tubeand dry ice condenser was charged with (3S,5R,6S)-tert-butyl3-ethyl-2-oxo-5,6-diphenyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)morpholine-4-carboxylate(0.57 g, 1.01 mmol) and THF (1 mL). After cooling the condenser to −78°C. and the flask to −45° C. (CO₂ (s), CH₃CN), ammonia (50 mL) wascondensed into the flask. Once complete, lithium metal (0.07 g, 10 mmol,small pieces) was carefully added over 10 min. After stirring anadditional 1 h, the reaction mixture was carefully quenched with NH₄Cl(s) until the solution became clear. The bath was removed and theammonia was allowed to evaporate over night. The resulting residue wasdiluted with ethyl acetate and washed successively with 0.5 N HCl andsaturated aqueous NaCl, dried over MgSO₄, filtered and concentrated. Thecrude product was dissolved in 50% methanol in toluene (50 mL, 0.1 M)and treated with TMSCHN₂ (2.0 M in hexanes) until the pale yellow colorpersisted. With TLC indicating the reaction complete, the excess TMSCHN₂was quenched with acetic acid until the solution became clear. Thesolution was concentrated, diluted with ethyl acetate and washedsuccessively with saturated aqueous NaHCO₃ and saturated aqueous NaCl,dried over MgSO₄, filtered and concentrated. Purification by MPLC (1-60%ethyl acetate in heptane over 4 CV) gave (S)-methyl2-(tert-butoxycarbonylamino)-2-ethyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas colorless oil (0.283 g, 71%). R_(f) 0.88 (30% ethyl acetate inheptane); ESI-LCMS m/z calcd for C₂₀H₃₈BNO₆: 399.3. found 400.3 (M+1)⁺.

Step 3: (S)-2-amino-6-borono-2-ethylhexanoic acid hydrochloride

A solution of (S)-methyl2-(tert-butoxycarbonylamino)-2-ethyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(0.283 g, 0.709 mmol) in 6 N HCl (5 mL) was heated to a gentle refluxfor 16 h. After cooling to room temperature, the reaction mixture wastransferred to a separatory funnel, diluted with deionized water (5 mL)and washed with dichloromethane (3×10 mL). The aqueous layer wasconcentrated to give an off-white solid that was dissolved in deionizedwater (3 mL) and passed through a C-18 Isolute SPE column (20 g) elutedwith 10% methanol in deionized water (200 mL). The fractions containingproduct were concentrated under reduced pressure, redissolved indeionized water (5 mL), frozen in liquid nitrogen and lyophilized togive (S)-2-amino-6-borono-2-ethylhexanoic acid hydrochloride as an whitefoam (0.096 g, 67%). ¹H NMR (D₂O, 300 MHz) δ□(m, 4H), 1.31-1.17 (m, 3H),1.13-0.97 (m, 1H), 0.794 (t, J=7.6 Hz, 3H), 0.63 (t, J=7.8 Hz, 2H);ESI-LCMS m/z calcd for C₈H₁₈BNO₄:203.1. found 204.1 (M+1)⁺.

Example 16: Preparation of(R/S)-2-Amino-6-borono-2-[2-pyrrolidin-1-yl)-ethyl]-hexanoic acidhydrochloride Step 1: ethyl2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of N-(diphenylmethylene)glycine ethyl ester (8.24 g, 30.8mmol) and 2-(4-bromobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (8.92g, 33.9 mmol) in freshly distilled THF (77 mL, 0.4 M) was cooled to −78°C. and treated with lithium bis(trimethylsilyl)amide (32.3 mL, 1.0 M inTHF). Once the addition was complete, the reaction was warmed to 50° C.and heated for 8 h. After being complete by TLC, the reaction mixturewas cooled to 0° C., diluted with ethyl acetate and washed successivelywith saturated aqueous NaHCO₃ and saturated aqueous NaCl, dried overMgSO₄, filtered and concentrated. Rapid purification by MPLC (1-15%ethyl acetate in heptane with 0.5% triethylamine over 6 CV) gave ethyl2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas a colorless oil (8.9 g, 64%). R_(f) 0.40 (30% ethyl acetate inheptane).

Step 2: ethyl2-allyl-2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of ethyl2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(2.79 g, 6.21 mmol) in freshly distilled (THF 15 mL, 0.4 M) was cooledto −78° C. and treated with lithium bis(trimethylsilyl)amide (6.8 mL,1.0 M in THF). After stirring for 10 min allyl bromide (2.25 g, 18.6mmol) was added the reaction was warmed to room temperature and stirredfor 16 h. After being complete by TLC, the reaction mixture was cooledto 0° C., diluted with ethyl acetate and washed successively withsaturated aqueous NaHCO₃ and saturated aqueous NaCl, dried over MgSO₄,filtered and concentrated. Purification by MPLC (1-20% ethyl acetate inheptane with 0.5% triethylamine over 6 CV) gave ethyl2-allyl-2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas a colorless oil (1.81 g, 59%). R_(f) 0.52 (30% ethyl acetate inheptane); ¹H NMR (CDCl₃, 300 MHz) δ 7.58-7.53 (m, 2H), 7.39-7.22 (m,6H), 7.16-7.12 (m, 2H), 5.89-5.74 (m, 1H), 5.07 (dd, J₁=15.3 Hz, J₂=2.1Hz, 1H), 5.05 (dd, J₁=8.7 Hz, J₂=2.1 Hz, 1H), 3.70 (q, J=7.5 Hz,1H_(diasterotopic)), 3.69 (q, J=7.2 Hz, 1H_(diasterotopic)), 2.70 (dd,J₁=7.2 Hz, J₂=1.2 Hz, 2H), 1.92-1.83 (m, 2H), 1.44-1.35 (m, 2H),1.35-1.23 (m, 2H), 1.19 (s, 12H), 1.10 (t, J=7.2 Hz, 3H), 0.78 (t, J=6.6Hz, 2H).

Step 3: ethyl2-allyl-2-amino-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of ethyl2-allyl-2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(0.32 g, 0.65 mmol) in diethyl ether (3.4 mL, 0.2 M) was treated with 1NHCl (3 mL). After stirring 16 h, the layers were separated and theaqueous phase was diluted with saturated aqueous K₂CO₃ and extractedwith chloroform to give ethyl2-allyl-2-amino-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas a colorless oil (0.20 g, 94%). R_(f) 0.62 (10% methanol indichloromethane); ¹H NMR (CDCl₃, 300 MHz) δ 5.76-5.60 (m, 1H), 5.18-5.07(m, 2H), 4.15 (q, J=7.2 Hz, 2H), 2.54 (ddt, J₁=13.5 Hz, J₂=6.3 Hz,J₃=1.2 Hz, 1H), 2.23 (dd, J₁=13.5 Hz, J₂=8.7 Hz, 1H), 1.8-1.68 (m, 2H),1.70-1.60 (m, 1H), 1.60-1.46 (m, 2H), 1.46-1.32 (m, 3H), 1.24 (s, 12H),1.20-1.06 (m, 1H), 0.766 (t, J=7.8 Hz, 2H); ESI-LCMS m/z calcd forC₁₇H₃₂BNO₄: 325.2. found 326.2 (M+H)⁺.

Step 4: ethyl2-allyl-2-amino-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of ethyl2-allyl-2-amino-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(0.0897 g, 0.276 mmol) in ethyl acetate (0.6 mL, 0.5 M) and saturatedaqueous NaHCO₃ (0.6 mL) was treated with di-tert-butyl carbonate (0.090g, 0.414 mmol) and stirred at room temperature. After 16 h, the layerswere separated and the aqueous layer was extracted with ethyl acetate.The combined organic layers were washed with saturated aqueous NaCl,dried over MgSO₄, filtered and concentrated. Purification by MPLC (0-20%ethyl acetate in heptane over 6 CV) gave ethyl2-allyl-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas a colorless oil (0.096 g, 82%). R_(f) 0.53 (30% ethyl acetate inheptane); ESI-LCMS m/z calcd for C₂₂H₄₀BNO₆: 425.3. found 426.3 (M+H)⁺.

Step 5:2-tert-Butoxycarbonylamino-2-(2-oxo-ethyl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-hexanoicacid ethyl ester

A solution ofEthyl-2-allyl-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(650 mg, 1.53 mmol) in dichloromethane (30 mL,) was cooled to −78° C.and treated with ozone until a pale blue-gray color appeared. After TLCindicated the absence of starting material, the ozone inlet tube wasreplaced with nitrogen and nitrogen was bubbled through the solution for20 min to remove any excess ozone. Triphenylphosphine (1.20 g, 4.59mmol, 3 equiv) was added in one portion, the cooling bath was removedand the mixture was stirred for 4 h. The solution was concentrated andpurified by MPLC (0-40% ethyl acetate in heptane) gave the titlecompound as a colorless oil (608 mg, 93%). R_(f) 0.25 (30% ethyl acetatein heptane); ¹H NMR (CDCl₃, 300 MHz): δ 9.64 (s, CHO, 1H), 5.60 (br, s,NH, 1H), 4.19 (q, J=7.5 Hz, 2H), 3.56 (d, J=17 Hz, 1H), 2.93 (d, J=17.5Hz, 1H), 2.20 (m, 1H), 1.62 (m, 1H), 1.38 (s, 9H), 1.28-1.43 (m, 4H),1.23 (t, J=7 Hz, 3H), 1.21 (s, 12H) and 0.72 (t, J=7.5 Hz, 2H).

Step 6:2-tert-Butoxycarbonylamino-2-(2-pyrrolidin-yl-ethyl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-hexanoicacid ethyl ester

A solution of2-tert-Butoxycarbonylamino-2-(2-oxo-ethyl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-hexanoicacid ethyl ester (100 mg, 0.23 mmol, 1.0 equiv.) and pyrrolidine (21 mg,0.29 mmol, 1.2 equiv.) in 1,2-dichloroethane (0.5 mL) was treated withsodium triacetoxyborohydride (125 mg, 0.59 mmol) in one portion. Afterstirring at room temperature overnight, the reaction mixture wasquenched with saturated aqueous NaHCO₃ (1 mL) and stirred for anadditional 5 min. The resulting mixture was added to a separatoryfunnel, diluted with saturated aqueous NaCl (5 mL) and extracted withdichloromethane (2×10 mL). The organic layer was dried over MgSO₄,filtered and concentration under reduced pressure. Purification by flashcolumn chromatography eluting with 5% methanol in chloroform to give2-tert-butoxycarbonylamino-2-(2-pyrrolidin-yl-ethyl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-hexanoicacid ethyl ester as a pale yellow oil (92 mg, 83%). R_(f) 0.32 (10%methanol in dichloromethane); ¹H NMR (CDCl₃, 300 MHz) δ 5.67 (br, s, NH,1H), 4.19 (m, 2H), 2.46-2.82 (m, 6H), 2.18 (m, 2H), 1.88 (m, 3H), 1.76(m, 2H), 1.42 (s, 9H), 1.26-1.41 (m, 3H), 1.28 (t, J=7.0 Hz, 3H), 1.22(s, 12H), 1.06 (m, 1H) and 0.73 (t, J=7.5 Hz, 2H).

Step 7: 2-Amino-6-borono-2-[2-pyrrolidin-1-yl)-ethyl]-hexanoic aciddihydrochloride

A solution of(R)-2-tert-butoxycarbonylamino-2-(2-pyrrolidin-1-yl-ethyl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (98 mg) in 6 N hydrochloric acid (5 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give2-amino-6-borono-2-[2-pyrrolidin-1-yl)-ethyl]-hexanoic aciddihydrochloride, as a colorless foam (36 mg, 53%); ¹H NMR (D₂O, 300 MHz)δ 3.47 (m, 2H), 3.24 (m, 1H), 3.07 (m, 1H), 2.88 m, 2H), 2.12 (t, J=8Hz, 2H), 1.94 (m, 2H), 1.60-1.82 (m, 4H), 1.20 (m, 3H), 1.04 (m, 1H) and0.59 (t, J=7 Hz, 2H); MS (+CI): m/z for C₁₂H₂₅BN₂O₄: expected 272.2.found 273.2 (M+H)⁺.

Example 17: Preparation of2-Amino-6-borono-2-[2-(4-pyrimidin-2-yl-piperazin-1-yl)ethyl]-hexanoicacid trihydrochloride

2-Amino-6-borono-2-[2-(4-pyrimidin-2-yl-piperazin-1-yl)ethyl]-hexanoicacid trihydrochloride is prepared in a manner analogous to that setforth in Example 16, except 1-2-(1-piperidinyl)pyrimidine is used as theamine in step 6. The final step is as follows: a solution of(R/S)-2-tert-butoxycarbonylamino-2-[2-(4-pyrimidin-2-yl-piperazin-1-yl)-ethyl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (126 mg) in 6 N hydrochloric acid (6 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give the title compound asa white solid (80 mg, 83%); ¹H NMR (D₂O, 300 MHz) δ 8.47 (d, J=5.5 Hz,2H), 6.96 (t, J=5.5 Hz, 1H), 3.48-3.76 (m, 4H), 3.14-3.40 (m, 6H), 2.29(t, J=8 Hz, 2H), 1.81 (m, 2H), 1.28 (m, 3H), 1.11 (m, 1H) and 0.62 (t,J=7.5 Hz, 2H).

Example 18: Preparation of2-amino-6-borono-2-(2-((carboxymethyl)(methyl)amino)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-((carboxymethyl)(methyl)amino)ethyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 16, except 2-(methylamino)acetic acid is used as the amine instep 6. The final step is as follows: a solution of(R/S)-2-tert-butoxycarbonylamino-2-[2-(2-ethoxycarbonylmethyl-methyl-amino)-ethyl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (138 mg) in 6 N hydrochloric acid (6 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give the title compound asa colorless foam (72 mg, 76%); ¹H NMR (D₂O, 300 MHz) δ 3.94 (s, 2H),3.37 (m, 1H), 3.20 (m, 1H), 2.83 (s, 3H), 2.24 (t, J=8 Hz, 2H),1.66-1.88 (m, 2H), 1.27 (m, 3H), 1.11 (m, 1H) and 0.63 (t, J=7.5 Hz,2H).

Example 19: Preparation of(R/S)-2-Amino-2-[2-(benzyl-ethyl-amino)-ethyl]-6-borono-hexanoic aciddihydrochloride

2-Amino-2-[2-(benzyl-ethyl-amino)-ethyl]-6-borono-hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 16, except ethylbenzylamine is used as the amine in step 6. Thefinal step is as follows: a solution of(R/S)-2-[2-(benzyl-ethyl-amino)-ethyl]-2-tert-butoxycarbonylamino-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (104 mg) in 6 N hydrochloric acid (6 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give the title compound asa colorless foam (41 mg); ¹H NMR (D₂O, 300 MHz) δ 7.36 (s, 5H), 4.31 (m,1H), 4.11 (m, 1H), 2.96-3.29 (m, 4H), 2.10 (m, 2H), 1.68 (m, 1H), 1.43(t, J=8 Hz, 1H), 1.21 (t, J=6.5 Hz, 3H), 0.89-1.20 (m, 4H),) and 0.59(m, 2H); MS (+CI): m/z for C₁₇H₂₉BN₂O₄: expected 336.2. found 337.2(M+H)⁺, 319 (M+H−H₂O)⁺.

Example 20: Preparation of2-Amino-2-{2-[benzyl-(2-hydroxyethyl)-amino]-ethyl}-6-borono-hexanoicacid dihydrochloride

2-Amino-2-{2-[benzyl-(2-hydroxyethyl)-amino]-ethyl}-6-borono-hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 2-(benzylamino)ethanol is used as the amine instep 6. The final step is as follows: a solution of2-{2-[benzyl-(2-hyrdoxyethyl)-amino]-ethyl}-2-tert-butoxycarbonylamino-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (111 mg) in 6 N hydrochloric acid (6 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give the title compound asa colorless foam (48 mg); ¹H NMR (D₂O, 300 MHz) δ 7.35 (s, 5H),4.11-4.25 (m, 2H), 3.76 (s, 2H), 3.06-3.34 (m, 4H), 2.18 (m, 2H), 1.76(m, 1H), 1.43 (m, 1H), 1.18 (m, 4H) and 0.56 (m, 2H); MS (+CI): m/z forC₁₇H₂₉BN₂O₅: expected 352.2. found 371.2 (M+H+H₂O)⁺, 353.2 (M+H)⁺, 335.2(M+H−H₂O)⁺.

Example 21: Preparation of(R/S)-1-[(3-Amino-7-borono-3-carboxy)-heptyl)-piperidine-4-carboxylicacid dihydrochloride

1-[(3-Amino-7-borono-3-carboxy)-heptyl)-piperidine-4-carboxylic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 16, except ethyl piperidine-4-carboxylate is used as the aminein step 6. The final step is as follows: a solution of2-tert-butoxycarbonylamino-2-[2-(4-methylcarbamoyl-piperidin-1-yl)-ethyl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (106 mg) in 6 N hydrochloric acid (6 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give the title compound asa colorless foam (34 mg); ¹H NMR (D₂O, 300 MHz) δ 3.50 (m, 1H), 3.22 (m,1H), 2.84-3.08 (m, 3H), 2.58 (tt, J₁=12 Hz, J₂=3.5 Hz, 1H), 2.14 (m,4H), 1.75 (m, 5H), 1.26 (m, 3H), 1.10 (m, 1H) and 0.64 (t, J=7.5 Hz,2H).

Example 22: Preparation of2-Amino-6-borono-2-[2-(4-hyrdoxymethylpiperidin-1-yl)-ethyl]-hexanoicacid dihydrochloride

(2-Amino-6-borono-2-[2-(4-hyrdoxymethylpiperidin-1-yl)-ethyl]-hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except piperidin-4-ylmethanol is used as the amine instep 6. The final step is as follows: a solution of(R)-2-tert-butoxycarbonylamino-2-[2-(4-hydroxymethyl-piperidin-1-yl)-ethyl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (78 mg) in 6 N hydrochloric acid (5 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give the title compound asa colorless foam (20 mg, 53%); ¹H NMR (D₂O, 300 MHz) δ 3.48 (m, 2H),3.33 (d, J=6 Hz, 2H), 3.21 (m, 1H), 3.04 (m, 1H), 2.86 (m, 2H), 2.19(2H, t, J=8.5 Hz), 1.86 (m, 2H), 1.60-1.78 (m, 3H), 1.20-1.36 (m, 5H),1.09 (m, 1H) and 0.64 (t, J=7.5 Hz, 2H); MS (+CI): m/z for C₁₂H₂₅BN₂O₄:expected 272.2. found 273.2 (M+H)⁺.

Example 23: Preparation of2-Amino-6-borono-2-[2-(3-diethylcarbamoyl-piperidin-1-yl)-ethyl]-hexanoicacid dihydrochloride

2-Amino-6-borono-2-[2-(3-diethylcarbamoyl-piperidin-1-yl)-ethyl]-hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except N,N-diethylpiperidine-3-carboxamide is used as theamine in step 6. The final step is as follows: a solution of (2R/S,3″R/S)-2-tert-butoxycarbonylamino-2-[2-(3-diethylcarbamoyl-piperidin-1-yl)-ethyl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (128 mg) in 6 N hydrochloric acid (5 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give a diastereomericmixture of the title compounds as a colorless foam (54 mg); ¹H NMR (D₂O,300 MHz) δ 3.46 (m, 2H), 3.26 (m, 4H), 3.10 (m, 2H), 2.94 (m, 4H), 2.20(m, 2H), 1.62-1.92 (6H, m), 1.28 (m, 2H), 1.10 (t, J=7.0 Hz, 3H), 1.06(m, 1H), 0.93 (t, J=7.0 Hz, 3H) and 0.64 (t, J=7.5 Hz, 2H); MS (+CI):m/z for C₁₈H₃₆BN₃O₅: expected 385.3. found 386.2 (M+H)⁺, 368.2(M+H−H₂O)⁺.

Example 24: Preparation of2-Amino-6-borono-2-(2-morpholin-4-yl)-ethyl)-hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-morpholin-4-yl)-ethyl)-hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 16, except morpholine is used as the amine in step 6. The finalstep is as follows: a solution of(R)-2-tert-butoxycarbonylamino-2-(2-morpholin-4-yl-ethyl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (102 mg) in 6 N hydrochloric acid (5 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give the title compound asa colorless foam (61 mg); ¹H NMR (D₂O, 300 MHz) δ 3.96 (d, J=12.5 Hz,2H), 3.66 (t, J=12.5 Hz, 2H), 3.40 (m, 2H), 3.10 (m, 4H), 2.20 (m, 2H),1.64-1.82 (m, 2H), 1.26 (m, 3H), 1.08 (m, 1H) and 0.62 (t, J=7.0 Hz,2H); MS (+CI): m/z for C₁₂H₂₅BN₂O₅: expected 288.2. found 289.2 (M+H)⁺.

Example 25: Preparation of2-Amino-2-[2-(4-benzylpiperidin-1-yl)ethyl]-6-borono-hexanoic aciddihydrochloride

2-Amino-2-[2-(4-benzylpiperidin-1-yl)ethyl]-6-borono-hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 16, except 4-benzylpiperidine is used as the amine in step 6.The final step is as follows: a solution of2-[2-(4-benzylpiperidin-1-yl)ethyl]-2-tert-butoxycarbonylamino-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (95 mg) in 6 N hydrochloric acid (5 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give the title compound asa colorless foam (42 mg); ¹H NMR (D₂O, 300 MHz) δ 7.24 (m, 2H), 7.13 (m,3H), 3.42 (m, 2H), 3.18 (m, 1H), 3.00 (m, 1H), 2.78 (m, 2H), 2.44 (d,J=7.0 Hz, 2H), 2.16 (t, J=7.0 Hz, 2H), 1.76 (m, 5H), 1.24 (m, 5H), 1.09(m, 1H) and 0.61 (t, J=7.0 Hz, 2H); MS (+CI): m/z for C₂₀H₃₃BN₂O₄:expected 376.3. found 377.2 (M+H)⁺, 359.2 (M+H−H₂O)⁺.

Example 26: Preparation of2-Amino-6-borono-2-[2-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)ethyl]-hexanoicacid dihydrochloride

2-Amino-6-borono-2-[2-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)ethyl]-hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline isused as the amine in step 6. The final step is as follows: a solution of2-tert-butoxycarbonylamino-2-[2-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)ethyl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxa-borolan-2-yl)-hexanoicacid ethyl ester (108 mg) in 6 N hydrochloric acid (5 mL) was stirred at95° C. overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give the title compound asa colorless foam (66 mg); ¹H NMR (D₂O, 300 MHz) δ 6.75 (s, 1H), 6.66 (s,1H), 4.39 (d, J=15 Hz, 1H), 4.14 (d, J=15 Hz, 1H), 3.67 (s, 3H), 3.66(s, 3H), 3.18-3.46 (m, 4H), 2.97 (m, 2H), 2.31 (t, J=8 Hz, 2H), 1.82 (m,2H), 1.27 (m, 3H), 1.12 (m, 1H) and 0.64 (m, 2H); MS (+CI): m/z forC₁₉H₃₁BN₂O₆: expected 394.2. found 395.5 (M+H)⁺, 377.4 (M+H−H₂O)⁺, 359.4(M+H−2H₂O)⁺.

Example 27: Preparation of2-amino-6-borono-2-(2-((4-methoxybenzyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-((4-methoxybenzyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 1-(4-methoxyphenyl)-N-methylmethanamine is used asthe amine in step 6. ¹H NMR (d₄-MeOH, 300 MHz) δ 7.47 (d, J=8.7 Hz, 2H),7.03 (d, J=9.0 Hz, 2H), 4.40 (d, J=11.2 Hz, 1H), 4.27 (d, J=11.2 Hz,1H), 3.83 (s, 3H), 2.82 (s, 3H), 2.43-2.38 (m, 2H), 1.95-1.81 (m, 2H),1.44-1.23 (m, 6H), 0.82 (t, J=7.5 Hz, 2H). ESI MS found for C₁₇H₂₉B₂NO₅m/z [353.6 (M+H)].

Example 28: Preparation of2-amino-6-borono-2-(2-(4-phenyl-5,6-dihydropyridin-1(2H)-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4-phenyl-5,6-dihydropyridin-1(2H)-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 4-phenyl-1,2,3,6-tetrahydropyridine is used as theamine in step 6. ¹H NMR (d₄-MeOH, 300 MHz) δ 7.67-7.64 (m, 1H),7.50-7.45 (m, 2H), 7.40-7.31 (m, 2H), 6.14 (s, 1H), 2.97-2.71 (m, 2H),2.49 (t, J=7.8 Hz, 2H), 2.08-1.92 (m, 4H), 1.59-1.19 (m, 8H), 0.84 (t,J=7.8 Hz, 2H). ESI MS found for C₁₉H₂₉B₁N₂O₄ m/z [325.5 (M+1)-2H₂O].

Example 29: Preparation of2-amino-6-borono-2-(2-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 4,5,6,7-tetrahydrothieno[3,2-c]pyridine is used asthe amine in step 6. ¹H NMR (d₄-MeOH, 300 MHz) δ 7.42 (d, J=5.1 Hz, 1H),6.91 (d, J=5.1 Hz, 1H), 3.60-3.53 (m, 2H), 2.50 (t, J=8.1 Hz, 2H),2.08-1.88 (m, 2H), 1.59-1.21 (m, 10H), 0.84 (t, J=7.5 Hz, 2H). ESI MSfound for C₁₅H₂₅B₁N₂O₄S₁ m/z [305.1 (M+1)-2H₂O].

Example 30: Preparation of2-amino-6-borono-2-(2-(3-oxo-2,3,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridin-5(4H)-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(3-oxo-2,3,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridin-5(4H)-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridin-3(2H)-one is used as theamine in step 6. ¹H NMR (d₄-MeOH, 300 MHz) δ 7.23-7.08 (m, 2H), 3.19 (s,2H), 2.54 (t, J=8.4 Hz, 2H), 2.08-1.89 (m, 4H), 1.50-1.28 (m, 8H), 0.84(t, J=6.9 Hz, 2H). ESI MS found for C₁₄H₂₅B₁N₂O₅ m/z [341.3 (M+1)].

Example 31: Preparation of2-amino-6-borono-2-(2-(4-(4-methoxyphenyl)-5,6-dihydropyridin-1(2H)-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4-(4-methoxyphenyl)-5,6-dihydropyridin-1(2H)-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 4-(4-methoxyphenyl)-1,2,3,6-tetrahydropyridine isused as the amine in step 6. ¹H NMR (d₄-MeOH, 300 MHz) δ 7.42 (d, J=8.7Hz, 2H), 6.92 (d, J=8.7 Hz, 2H), 6.40 (s, 1H), 3.80 (s, 3H), 2.88 (s,2H), 2.50-2.43 (m, 2H), 2.05-1.88 (m, 4H), 1.59-1.23 (m, 8H), 0.84 (t,J=7.2 Hz, 2H). (ESI MS found for C₂₀H₃₁B₁N₂O₅ m/z [373.5 (M+1)-H₂O].

Example 32: Preparation of2-amino-6-borono-2-(2-(piperazin-1-yl)ethyl)hexanoic acidtrihydrochloride

2-Amino-6-borono-2-(2-(piperazin-1-yl)ethyl)hexanoic acidtrihydrochloride is prepared in a manner analogous to that set forth inExample 16, except tert-butyl piperazine-1-carboxylate is used as theamine in step 6. The final compound was isolated as the trihydrochloridesalt. ¹H NMR (D₂O, 300 MHz) δ 3.55-3.30 (m, 9H), 3.26-3.14 (m, 1H),2.30-2.11 (m, 2H), 1.88-1.62 (m, 2H), 1.31-1.14 (m, 3H), 1.14-0.99 (m,1H), 0.60 (t, J=7.2 Hz, 2H). ESI MS found for C₁₂H₂₆BN₃O₄ m/z [288.2(M+1)].

Example 33: Preparation of2-amino-6-borono-2-(2-((S)-2-(methoxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-((S)-2-(methoxymethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except (S)-2-(methoxymethyl)pyrrolidine is used as theamine in step 6. ¹H NMR (D₂O, 300 MHz) δ 3.63-3.38 (m, 5H), 3.21 (s,3H), 3.07-2.95 (m, 2H), 2.24-1.60 (m, 8H), 1.32-1.17 (m, 3H), 1.15-0.98(m, 1H), 0.60 (t, J=7.2 Hz, 2H). ESI MS found for C₁₄H₂₉BN₂O₅ m/z [317.2(M+1)].

Example 34: Preparation of2-amino-2-(2-(4-benzyl-4-hydroxypiperidin-1-yl)ethyl)-6-boronohexanoicacid dihydrochloride

2-Amino-2-(2-(4-benzyl-4-hydroxypiperidin-1-yl)ethyl)-6-boronohexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 4-benzylpiperidin-4-ol is used as the amine instep 6. The final compound was isolated as the dihydrochloride salt. ¹HNMR (D₂O, 300 MHz) δ 7.20-7.01 (m, 5H), 3.32-3.10 (m, 3H), 3.06-2.90 (m,3H), 2.61 (s, 2H), 2.16 (t, J=8.4 Hz, 2H), 1.81-1.64 (m, 4H), 1.57 (d,J=14.7 Hz, 2H), 1.27-1.12 (m, 3H), 1.09-0.95 (m, 1H), 0.55 (t, J=7.2 Hz,2H). ESI MS found for C₂₀H₃₃BN₂O₅ m/z [393.2 (M+1)].

Example 35: Preparation of2-amino-6-borono-2-(2-(4-methylpiperazin-1-yl)ethyl)hexanoic acidtrihydrochloride

2-Amino-6-borono-2-(2-(4-methylpiperazin-1-yl)ethyl)hexanoic acidtrihydrochloride is prepared in a manner analogous to that set forth inExample 16, except 1-methylpiperazine is used as the amine in step 6.The final compound was isolated as the trihydrochloride salt. ¹H NMR(D₂O, 300 MHz) δ 3.90-3.12 (m, 9H), 2.84 (s, 3H), 2.30-2.11 (m, 2H),1.87-1.63 (m, 3H), 1.33-1.14 (m, 3H), 1.14-0.97 (m, 1H), 0.60 (t, J=7.5Hz, 2H). ESI MS found for C₁₃H₂₈BN₃O₄ m/z [302.2 (M+1)].

Example 36: Preparation of2-amino-6-borono-2-(2-(3,4-dihydroisoquinolin-2(1H)-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(3,4-dihydroisoquinolin-2(1H)-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 1,2,3,4-tetrahydroisoquinoline is used as theamine in step 6. ¹H NMR (D₂O, 300 MHz) δ 7.22-7.10 (m, 3H), 4.45(d_(AB), J=15.0 Hz, 1H), 4.21 (d_(AB), J=15.0 Hz, 1H), 3.72-3.62 (m,1H), 3.48-3.00 (m, 4H), 2.38-2.28 (m, 2H), 1.92-1.69 (m, 3H), 1.35-1.20(m, 3H), 1.18-1.03 (m, 1H), 0.62 (t, J=6.9 Hz, 2H). ESI MS found forC₁₇H₂₇BN₂O₄ m/z [335.2 (M+1)].

Example 37: Preparation of2-amino-6-borono-2-(2-(diethylamino)ethyl)hexanoic acid dihydrochloride

2-Amino-6-borono-2-(2-(diethylamino)ethyl)hexanoic acid dihydrochlorideis prepared in a manner analogous to that set forth in Example 16,except diethylamine is used as the amine in step 6. ¹H NMR (D₂O, 300MHz) δ 3.28-3.14 (m, 1H), 3.06 (q, J=7.2 Hz, 4H), 3.08-2.95 (m, 1H),2.21-2.11 (m, 2H), 1.89-1.68 (m, 2H), 1.31-1.17 (m, 3H), 1.09 (t, J=7.2Hz, 6H), 1.08-0.98 (m, 1H), 0.60 (t, J=7.5 Hz, 2H). ESI MS found forC₁₂H₂₇BN₂O₄ m/z [275.2 (M+1)].

Example 38: Preparation of2-amino-6-borono-2-(2-(4-oxopiperidin-1-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(4-oxopiperidin-1-yl)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except piperidin-4-one is used as the amine instep 6. ¹H NMR (D₂O, 500 MHz) δ 3.54-3.47 (m, 2H), 3.32 (dt, J=5.0, 6.0Hz, 1H), 3.15-3.07 (m, 3H), 2.28-2.18 (m, 2H), 2.01-1.84 (m, 5H),1.78-1.72 (m, 1H), 1.37-1.27 (m, 3H), 1.20-1.10 (m, 1H), 0.70 (t, J=8.0Hz, 2H). ESI MS found for C₁₃H₂₅BN₂O₅ m/z [283.6 (M+1−18) 7%, 265.5(M+1−2×18) 100%].

Example 39: Preparation of2-amino-6-borono-2-(2-(4-(trifluoromethyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4-(trifluoromethyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except 4-(trifluoromethyl)piperidine isused as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 3.63 (t, J=12.0 Hz,2H) 3.31 (ddd, J₁=12.0 Hz, J₂=10.0 Hz, J₃=6.0 Hz, 1H), 3.11 (ddd,J₁=12.0 Hz, J₂=11.0 Hz, J₃=6.0 Hz, 1H), 3.03-2.94 (m, 2H), 2.59-2.49 (m,1H), 2.28-2.21 (m, 2H), 2.16-2.13 (m, 2H), 1.89-1.84 (m, 1H), 1.78-1.69(m, 3H), 1.37-1.27 (m, 3H), 1.19-1.10 (m, 1H), 0.70 (t, J=8.0 Hz, 2H).¹⁹F NMR −73.45 (s, 3F). ESI MS found for C₁₄H₂₆BF₃N₂O₄ m/z [337.6(M+1−18) 13%, 319.5 (M+1−2×18) 100%].

Example 40: Preparation of2-amino-6-borono-2-(2-((S)-2-(pyrrolidin-1-ylmethyl)pyrrolidin-1-yl)ethyl)hexanoicacid trihydrochloride

2-Amino-6-borono-2-(2-((S)-2-(pyrrolidin-1-ylmethyl)pyrrolidin-1-yl)ethyl)hexanoicacid trihydrochloride is prepared in a manner analogous to that setforth in Example 16, except (S)-1,2′-methylenedipyrrolidine is used asthe amine in step 6. The final compound was isolated as thetrihydrochloride salt and monohydrate. ¹H NMR (D₂O, 500 MHz) δ 3.89-3.81(m, 1H), 3.72-3.65 (m, 4H), 3.53 (dd, J=12.0 Hz, J₂=4.0 Hz, 1H), 3.43(dd, J=12.0 Hz, J₂=6.0 Hz, 1H), 2.28-2.17 (m, 2H), 2.16-2.01 (m, 4H),1.94-1.83 (m, 4H), 1.76-1.71 (m, 1H), 1.37-1.32 (m, 3H), 1.18-1.09 (m,1H), 0.69 (t, J=8.0 Hz, 2H). ESI MS found for C₁₇H₃₄BN₃O₄ m/z [338.7(M+1−18) 29%, 320.6 (M+1−2×18) 100%, 336.7 (M−1−18) 100%].

Example 41: Preparation of2-amino-6-borono-2-(2-(4-methoxypiperidin-1-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(4-methoxypiperidin-1-yl)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except 4-methoxypiperidine is used as the aminein step 6. ¹H NMR (D₂O, 500 MHz) δ 3.60-3.49 (m, 2H), [3.29 (s, 1^(st)conformer), 3.26 (s, 2^(nd) conformer), 3H], 3.33-3.24 (m, 2H),3.12-3.04 (m, 2H), 3.02-2.93 (m, 1H), 1.88-1.75 (m, 3H), 1.57-1.48 (m,1H), 1.38-1.27 (m, 3H), 1.19-1.09 (m, 1H), 0.68 (t, J=8.0 Hz, 2H). ESIMS found for C₁₄H₂₉BN₂O₅ m/z [299.6 (M+1−18) 15%, 281.5 (M+1−2×18) 100%,297.6 (M−1−18) 75%].

Example 42: Preparation of2-amino-2-(2-(2-(benzofuran-2-yl)pyrrolidin-1-yl)ethyl)-6-boronohexanoicacid dihydrochloride

2-Amino-2-(2-(2-(benzofuran-2-yl)pyrrolidin-1-yl)ethyl)-6-boronohexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except 2-(benzofuran-2-yl)pyrrolidine isused as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 7.62 (dd, J₁=8.0Hz, J₂=8.0 Hz, 1H), 7.51 (dd, J₁=8.0 Hz, J₂=4.0 Hz, 1H), 7.31-7.37 (m,1H), 7.22-7.27 (m, 1H), [7.12 (s, 1^(st) diastereoisomer), 7.09 (s,2^(nd) diastereoisomer), 1H], 4.78-4.61 (m, 3H), 3.82-3.75 (m, 1H),3.59-3.52 (m, 1H), 3.40-3.31 (m, 1H), 3.25-3.12 (m, 1H), 2.52-2.40 (m,2H), 2.30-2.12 (m, 3H), [1.97-1.93 (m, 1^(st) diastereoisomer),2.05-2.00 (m, 2^(nd) diastereoisomer), 1H], 1.28-1.00 (m, 4H),[0.55-0.43 (m, 1^(st) diastereoisomer), 0.81-0.62 (m, 2^(nd)diastereoisomer), 2H]. ESI MS found for C₂₀H₂₉BN₂O₅ m/z [371.6 (M+1-18)16%, 353.6 (M+1−2×18) 100%].

Example 43: Preparation of2-amino-6-borono-2-(2-((2-hydroxyethyl)(methyl)amino)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-((2-hydroxyethyl)(methyl)amino)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except 2-(methylamino)ethanol is used as theamine in step 6. ¹H NMR (D₂O, 500 MHz) δ 3.81 (brt, J=5.0 Hz, 2H),3.55-3.42 (m, 1H), 3.36-3.13 (m, 3H), [2.84 (s, 1^(st) rotamer), 2.83(s, 2^(nd) rotamer), 3H], 2.27 (brt, J=7.0 Hz, 2H), 1.92-1.87 (m, 1H),1.81-1.75 (m, 1H), 1.37-1.29 (m, 3H), 1.18-1.13 (m, 1H), 0.70 (t, J=7.0Hz, 2H). ESI MS found for C₁₁H₂₅BN₂O₅ m/z [277.6 (M+1) 5%, 259.6(M+1−18) 25%, 241.5 (M+1−2×18) 100%, 257.6 (M−1−18) 100%].

Example 44: Preparation of2-amino-6-borono-2-(2-(3,3-difluoropyrrolidin-1-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(3,3-difluoropyrrolidin-1-yl)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except 3,3-difluoropyrrolidine is used as theamine in step 6. ¹H NMR (D₂O, 500 MHz) δ 3.95-3.85 (m, 2H), 3.79-3.69(m, 2H), 3.54 (ddd, J₁=12.0 Hz, J₂=10.0 Hz, J₃=6.0 Hz, 1H), 3.35 (ddd,J₁=12.0, J₂=10.0, J₃=5.0 Hz, 1H), 2.68-2.63 (m, 2H), 2.29-2.22 (m, 2H),1.79 (ddd, J=15.0, J₂=12.0, J₃=5.0 Hz, 1H), 1.40-1.32 (m, 3H), 1.22-1.15(m, 1H), 0.73 (t, J=7.0 Hz, 2H). ESI MS found for C₁₂H₂₃BF₂N₂O₄ m/z[291.5 (M+1−18) 17%, 273.5 (M+1−2×18) 100%, 307.6 (M−1) 29%, 289.5(M−1−18) 100%].

Example 45: Preparation of2-(2-(4-acetyl-4-phenylpiperidin-1-yl)ethyl)-2-amino-6-boronohexanoicacid dihydrochloride

2-(2-(4-Acetyl-4-phenylpiperidin-1-yl)ethyl)-2-amino-6-boronohexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except 1-(4-phenylpiperidin-4-yl)ethanoneis used as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 7.27-7.44 (m,5H), 3.64-3.60 (m, 1H), 3.56-3.52 (m, 1H), 3.33-3.08 (m, 2H), 3.04-2.89(m, 2H), 2.85-2.82 (m, 2H), 2.29-2.25 (m, 1H), 2.21-2.13 (m, 2H),2.11-2.03 (m, 1H), [1.93 (s, 1^(st) conformer), 1.91 (s, 2^(nd)conformer), 3H], 1.88-1.69 (m, 2H), 1.37-1.25 (m, 3H), 1.16-1.09 (m,1H), [0.69 (t, J=7.0 Hz, 1^(st) conformer), 0.67 (t, J=7.0 Hz, 2^(nd)conformer), 2H]. ESI MS found for C₂₁H₃₃BN₂O₅ m/z [387.7 (M+1−18) 30%,369.6 (M+1−2×18) 100%].

Example 46: Preparation of2-amino-6-borono-2-(2-((R)-2-(trifluoromethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-((R)-2-(trifluoromethyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except (R)-2-(trifluoromethyl)pyrrolidineis used as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 4.44-4.34 (m,1H), 3.78-3.71 (m, 1H), [3.54-3.47 (m, 1^(st) diastereoisomer),3.69-3.65 (m, 2^(st) diastereoisomer), 1H], [3.37-3.32 (m, 1^(st)diastereoisomer), 3.46-3.41 (m, 2^(st) diastereoisomer), 1H], 3.29-3.19(m, 1H), 2.44-2.35 (m, 1H), 2.33-2.27 (m, 1H), 2.22-2.13 (m, 3H),2.05-1.96 (m, 1H), 1.92-1.86 (m, 1H), 1.80-1.73 (m, 1H), 1.35-1.29 (m,3H), 1.20-1.11 (m, 1H), 0.69 (t, J=7.0 Hz, 2H). ¹⁹F NMR [−71.29 (s,1^(st) diastereoisomer), −71.06 (s, 2^(nd) diastereoisomer), 3F]. ESI MSfound for C₁₃H₂₄BF₃N₂O₄ m/z [323.5 (M+1−18) 10%, 305.5 (M+1−2×18) 100%,321.5 (M−1−18) 100%].

Example 47: Preparation of2-amino-6-borono-2-(2-(4-fluoropiperidin-1-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(4-fluoropiperidin-1-yl)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except 4-fluoropiperidine is used as the aminein step 6. ¹H NMR (D₂O, 500 MHz) δ 5.00 (brd, J=47 Hz, 0.7H), 4.85 (dsept. J=47 Hz 0.08H), 3.65-3.58 (m, 0.3H), 3.48-3.44 (m, 1.5H),3.37-3.33 (m, 1H), 3.27-3.20 (m, 1.5H), 3.19-3.14 (m, 1H), 3.12-3.06 (m,0.3H), 2.34-2.26 (m, 2H), 2.24-2.20 (m, 2H), 2.05-1.88 (m, 3H), 1.81(ddd, J=14.0, 12.0, 4.0 Hz, 1H), 1.40-1.32 (m, 3H), 1.22-1.16 (m, 1H),0.73 (t, J=7.0 Hz, 2H). ¹⁹F NMR [−188.10-−188.05 (m, 1^(st) conformer),−177.96-−177.87 (m, 2^(nd) conformer), 1F].

Example 48: Preparation of2-amino-6-borono-2-(2-((4-fluoro-3-(trifluoromethyl)benzyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-((4-fluoro-3-(trifluoromethyl)benzyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except1-(4-fluoro-3-(trifluoromethyl)phenyl)-N-methylmethanamine is used asthe amine in step 6. ¹H NMR (D₂O, 500 MHz) δ [7.80 (brs, 1^(st)rotamer), 7.79 (brs, 2^(nd) rotamer), 1H], 7.75-7.69 (m, 1H), 7.36 (dd,J₁=10.0 Hz, J₂=8.0 Hz, 1H), 4.45-4.36 (m, 1H), 4.32-4.23 (m, 1H),3.43-3.37 (m, 1H), 3.13-3.05 (m, 1H), 2.79 (brs, 2^(nd) rotamer), 3H],[2.76 (brs, 1^(st) rotamer), 2.26 (dt, J₁=16.0 Hz, J₂=8.0 Hz, 1H),2.18-2.06 (m, 1H), 1.86-1.66 (m, 1H), 1.46-0.98 (m, 5H), 0.69-0.57 (m,2H). ¹⁹F NMR −112.29 (q, J=14.0 Hz, 1F), −60.85 (d, J=14.0 Hz, 3F). ESIMS found for C₁₇H₂₅BF₄N₂O₄ m/z [391.5 (M+1−18) 33%, 373.6 (M+1−2×18)100%].

Example 49: Preparation of2-amino-6-borono-2-(2-(4-methyl-1,4-diazepan-1-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(4-methyl-1,4-diazepan-1-yl)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except 1-methyl-1,4-diazepane is used as theamine in step 6. ¹H NMR (D₂O, 500 MHz) δ 3.77-3.68 (m, 2H), 3.55-3.51(m, 3H), 3.47-3.41 (m, 2H), 3.28-3.23 (m, 1H), 2.91 (s, 3H), 2.29-2.23(m, 3H), 2.21-2.14 (m, 1H), 1.88-1.83 (m, 1H), 1.76-1.71 (m, 1H),1.37-1.27 (m, 3H), 1.18-1.10 (m, 1H), 0.70 (t, J=8.0 Hz, 2H). ESI MSfound for C₁₄H₃₀BN₃O₄ m/z [298.5 (M+1−18) 6%, 280.5 (M+1-2×18) 100%,268.5 (M+1-3×18) 5%].

Example 50: Preparation of2-amino-6-borono-2-(2-(4-(2-methoxyphenyl)piperazin-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4-(2-methoxyphenyl)piperazin-1-yl)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except 1-(2-methoxyphenyl)piperazine isused as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 7.15 (ddd, J₁=8.0Hz, J₂=8.0 Hz, J₃=1.0 Hz, 1H), 7.09 (dd, J₁=8.0 Hz, J₂=1.0 Hz, 1H), 7.01(d, J=8.0 Hz, 1H), 6.95 (dd, J₁=8.0 Hz, J₂=8.0 Hz, 1H), 3.78 (s, 3H),3.52-3.34 (m, 8H), 2.34-2.24 (m, 2H), 1.92-1.87 (m, 1H), 1.81-1.75 (m,1H), 1.49-1.44 (m, 2H), 1.37-1.29 (m, 3H), 1.20-1.15 (m, 1H), 0.70 (t,J=8.0 Hz, 2H). ESI MS found for C₁₉H₃₂BN₃O₅ m/z [376.6 (M+1−18) 10%,358.7 (M+1−2×18) 100%].

Example 51: Preparation of2-amino-2-(2-(bis(2-aminoethyl)amino)ethyl)-6-boronohexanoic acidtetrahydrochloride

2-Amino-2-(2-(bis(2-aminoethyl)amino)ethyl)-6-boronohexanoic acidtetrahydrochloride is prepared in a manner analogous to that set forthin Example 16, except tert-butyl2,2′-azanediylbis(ethane-2,1-diyl)dicarbamate is used as the amine instep 6. The final compound was isolated as the tetrahydrochloride saltand monohydrate. ¹H NMR (D₂O, 500 MHz) δ 3.15-3.12 (m, 4H), 3.00-2.92(m, 5H), 2.77 (ddd, J₁=14.0 Hz, J₂=7.0 Hz, J₃=6.0 Hz, 1H), 2.07 (t,J=7.0 Hz, 2H), 1.86 (ddd, J₁=18.0 Hz, J₂=14.0 Hz, J₃=4.0 Hz, 1H), 1.76(ddd, J₁=18.0 Hz, J₂=14.0 Hz, J₃=4.0 Hz, 1H), 1.37-1.32 (m, 3H),1.17-1.09 (m, 1H), 0.69 (t, J=7.0 Hz, 2H). ESI MS found for C₁₂H₂₉BN₄O₄m/z [287.6 (M+1−18) 5%, 269.5 (M+1−2×18) 100%, 303.6 (M−1) 28%, 285.6(M−1−18) 100%].

Example 52: Preparation of1-(3-amino-7-borono-3-carboxyheptyl)piperidine-2-carboxylic aciddihydrochloride

1-(3-Amino-7-borono-3-carboxyheptyl)piperidine-2-carboxylic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except piperidine-2-carboxylate is used as theamine in step 6. ¹H NMR (D₂O, 500 MHz) δ 3.98-3.88 (m, 1^(st)conformer), 1H), 3.64 (brd, J=13.0 Hz, 1H), 3.44 (dt, J₁=13.0 Hz, J₂=6.0Hz, 2^(nd) conformer), 3.32-3.25 (m, 2H), 3.10 (dt, J₁=13.0 Hz, J₂=5.0Hz, 2^(nd) conformer), 1H], [3.03-2.96 (m, 1^(st) conformer), 2.42-2.36(m, 1H), 2.35-2.30 (m, 1H), 2.24 (brd, J=14.0 Hz, 1H), 1.94-1.88 (m,2H), 1.84-1.81 (m, 2H), 1.78-1.72 (m, 1H), 1.70-1.64 (m, 1H), 1.55-1.50(m, 1H), 1.38-1.32 (m, 3H), 1.21-1.16 (m, 1H), 0.72 (t; J=7.0 Hz, 2H).ESI MS found for C₁₂H₂₉BN₄O₄ m/z [317.5 (M+Na⁺−2×18) 11%, 313.6 (M+1−18)17%, 295.6 (M+1−2×18) 100%, 329.5 (M−1)₆%, 311.6 (M−1−18) 100%].

Example 53: Preparation of1-(3-amino-7-borono-3-carboxyheptyl)piperidine-2-carboxylic aciddihydrochloride

1-(3-Amino-7-borono-3-carboxyheptyl)piperidine-2-carboxylic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except (R)-piperidine-3-carboxylate is used asthe amine in step 6. ¹H NMR (D₂O, 500 MHz) δ (two diastereoisomers+twoconformers) 3.78 (brt, J=12.0 Hz, 0.35H), 3.73 (brt, J=12.0 Hz, 0.65H),3.54 (brt, J=14.0 Hz, 0.65H), 3.43 (brt, J=14.0 Hz, 0.35H), 3.39-3.33(m, 1H), 3.19-3.13 (m, 1H), 3.11-3.08 (m, 1H), 3.05-2.80 (m, 2H),2.40-2.19 (m, 2H), 2.17-2.11 (m, 1H), 2.02 (brd, J=15.0 Hz, 0.65H),1.94-1.67 (m, 3.70H), 1.55 (ddd, J₁=16.0 Hz, J₂=13.0 Hz, J₃=4.0 Hz,0.65H), 1.39-1.33 (m, 3H), 1.22-1.15 (m, 1H), 0.74 (t, J=7.0 Hz, 2H).ESI MS found for C₁₂H₂₉BN₄O₄ m/z [317.4 (M+Na⁺−2×18) 5%, 313.6 (M+1-18)10%, 295.6 (M+1−2×18) 100%, 311.6 (M−1−18) 100%].

Example 54: Preparation of2-amino-6-borono-2-(2-((S)-2-(dimethylcarbamoyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-((S)-2-(dimethylcarbamoyl)pyrrolidin-1-yl)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except(S)—N,N-dimethylpyrrolidine-2-carboxamide is used as the amine in step6. ESI MS found for C₁₃H₂₆BN₃O₅ m/z [298.5 (M+1−18) 15%, 280.5(M+1−2×18) 55%, 235.5 (M+1−2×18−45) 100%].

Example 55: Preparation of2-amino-6-borono-2-(2-(isopropylamino)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(isopropylamino)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except isopropylamine is used as the amine instep 6. ¹H NMR (D₂O, 500 MHz) δ 3.26 (septet, J=6.0 Hz, 1H), 3.10-3.0.5(m, 1H), 2.84-2.80 (m, 1H), 2.12 (t, J=8.0 Hz, 2H), 1.80-1.71 (m, 2H),1.34-1.27 (m, 3H), 1.19 (d, J=6.0 Hz, 6H), 1.11-1.07, (m, 1H), 0.58 (t,J=7.0 Hz, 2H). ESI MS found for C₁₁H₂₅BN₂O₄ m/z [261.6 (M+1) 3%, 243.5(M+1−18) 30%, 225.5 (M+1−2×18) 100%, 207.5 (M+1−3×18) 62%, 501.9 (2M−1−18) 13%, 259.6 (M−1) 23%, 241.5 (M−1−18) 100%].

Example 56: Preparation of(3S)-1-(3-amino-7-borono-3-carboxyheptyl)piperidine-3-carboxylic aciddihydrochloride

(3S)-1-(3-Amino-7-borono-3-carboxyheptyl)piperidine-3-carboxylic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except (S)-ethyl piperidine-3-carboxylate isused as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ (twodiastereoisomers+two conformers) 3.79 (brt, J=12.0 Hz, 0.35H), 3.74(brt, J=12.0 Hz, 0.65H), 3.55 (brt, J=12.0 Hz, 0.65H), 3.44 (brt, J=12.0Hz, 0.35H), 3.41-3.33 (m, 1H), 3.21-3.15 (m, 1H), 3.13-2.95 (m, 2H),2.92-2.81 (m, 1H), 2.42-2.11 (m, 3H), 2.03 (brd, J=14.0 Hz, 0.65H),1.94-1.70 (m, 3.80H), 1.57 (dq, J=13.0, 4.0 Hz, 0.65H), 1.40-1.32 (m,3H), 1.24-1.15 (m, 1H), 0.74 (t, J=7.0 Hz, 2H). ESI MS found forC₁₄H₂₇BN₂O₆ m/z [313.6 (M+1−18) 10%, 295.5 (M+1−2×18) 100%, 277.5(M+1−3×18) 15%].

Example 57: Preparation of1-(3-amino-7-borono-3-carboxyheptyl)-4-methylpiperidine-4-carboxylicacid

(2-(2-(4-Acetyl-4-methylpiperidin-1-yl)ethyl)-2-amino-6-boronohexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except 1-(4-methylpiperidin-4-yl)ethanoneis used as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ (two conformersin ratio 3/1) 3.48-3.40 (m, 2H), 3.34-3.21 (m, 1H), 3.15-3.11 (m, 0.5H),3.08-3.02 (m, 1H), 2.96-2.87 (m, 1.5H), 2.28 (d, J=14.0 Hz, 1.5H),2.23-2.19 (m, 2H), 2.06-2.01 (m, 0.5H), 1.88-1.82 (m, 1.5H), 1.77-1.71(m, 1H), 1.61 (t, J=14.0 Hz, 1.5H), 1.34-1.27 (m, 3H), [1.25 (s, 1^(st)conformer), 1.18 (s, 2^(nd) conformer), 3H], 1.16-1.10 (m, 1H), 0.69 (t,J=8.0 Hz, 2H). ESI MS found for C₁₅H₂₉BN₂O₆ m/z [327.6 (M+1−18) 13%,309.6 (M+1−2×18) 100%, 291.6 (M+1−3×18) 10%, 325.6 (M−1-18) 100%, 307.6(M−1-2×18) 37%].

Example 58: Preparation of2-amino-6-borono-2-(2-(2,3-dihydro-1H-inden-2-ylamino)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(2,3-dihydro-1H-inden-2-ylamino)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except 2,3-dihydro-1H-inden-2-amine isused as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 7.26-7.24 (m, 2H),7.21-7.19 (m, 2H), 4.09-4.04 (m, 1H), 3.35 (dd, J₁=17.0 Hz, J₂=7.0 Hz,2H), 3.31-3.25 (m, 1H), 3.12-3.07 (m, 1H), 3.04 (dd, J₁=17.0 Hz, J₂=4.0Hz, 2H), 2.18 (t, J=8.0 Hz, 2H), 1.91-1.86 (m, 1H), 1.79-1.73 (m, 1H),1.38-1.27 (m, 3H), 1.20-1.11 (m, 1H), 0.71 (t, J=8.0 Hz, 2H). ESI MSfound for C₁₃H₂₆BFN₂O₄ m/z [317.5 (M+1−18) 28%, 299.6 (M+1−2×18) 100%,281.5 (M+1−3×18) 31%, 333.5 (M−1) 28%, 315.5 (M−1−18) 100%].

Example 59: Preparation of2-amino-6-borono-2-(2-(3-hydroxyazetidin-1-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(3-hydroxyazetidin-1-yl)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except azetidin-3-ol is used as the amine instep 6. ¹H NMR (D₂O, 500 MHz) δ 4.65-4.60 (m, 1H), 4.50-4.46 (m, 1H),4.21-4.17 (m, 1H), 4.10-4.08 (m, 1H), 3.86-3.82 (m, 1H), 3.48-3.37 (m,1H), 3.30-3.19 (m, 1H), 2.09-2.04 (m, 2H), 1.90-1.85 (m, 1H), 1.78-1.73(m, 1H), 1.35-1.28 (m, 3H), 1.19-1.10 (m, 1H), 0.70 (t, J=7.0 Hz, 2H).ESI MS found for C₁₁H₂₃BN₂O₅ m/z [275.5 (M+1) 5%, 257.5 (M+1−18) 11%,239.4 (M+1−2×18) 100%, 273.5 (M−1) 10%, 255.5 (M−1−18) 100%].

Example 60: Preparation of2-amino-6-borono-2-(2-(1-butylcyclopropylamino)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(1-butylcyclopropylamino)ethyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 16, except 1-butylcyclopropanamine is used as the amine in step6 and dihydrate. ¹H NMR (D₂O, 500 MHz) δ 3.33-3.27 (m, 1H), 3.12-3.07(m, 1H), 2.15 (t, J=8.0 Hz, 2H), 1.91-1.86 (m, 1H), 1.79-1.73 (m, 1H),1.66-1.56 (m, 2H), 1.36-1.30 (m, 3H), 1.26 (brs, 4H), 1.17-1.11 (m, 1H),0.89 (s, 2H), 0.79-0.77 (m, 5H), 0.70 (t, J=7.0 Hz, 2H). ESI MS foundfor C₁₅H₃₁BN₂O₄ m/z [297.6 (M+1−18) 22%, 279.5 (M+1−2×18) 100%, 261.6(M+1−3×18) 17%, 313.6 (M−1) 19%, 295.6 (M−1−18) 100%]. Anal. Calcd forC₁₅H₃₁BN₂O₄×2HCl×2H₂O: C, 42.57; H, 8.81; N, 6.62. Found C, 41.19; H,8.24; N, 6.57.

Example 61: Preparation of2-amino-6-borono-2-(2-(1-(4-methoxybenzyl)cyclopropylamino)ethyl)hexanoicacid

2-Aamino-6-borono-2-(2-(1-(4-methoxyphenyl)cyclopropylamino)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 1-(4-methoxyphenyl)cyclopropanamine is used as theamine in step 6 and dihydrate. ¹H NMR (D₂O, 500 MHz) δ 7.26 (d, J=8.0Hz, 2H), 6.92 (d, J=8.0 Hz, 2H), 3.73 (s, 3H), 3.29-3.249 (m, 1H),3.11-3.05 (m, 1H), 2.97 (d, J=16.0 Hz, 1H), 2.93 (d, J=16.0 Hz, 1H),2.07-2.00 (m, 2H), 1.78-1.73 (m, 1H), 1.67-1.62 (m, 1H), 1.34-1.29 (m,2H), 1.27-1.21 (m, 1H), 1.12-1.07 (m, 1H), 1.00 (s, 2H), 0.94 (s, 2H),0.69 (t, J=8.0 Hz, 2H). ESI MS found for C₁₉H₃₁BN₂O₅ m/z [361.6 (M+1−18)16%, 343.6 (M+1−2×18) 100%, 325.5 (M+1-3×18) 16%, 377.7 (M−1) 17%, 359.6(M−1−18) 100%]. Anal. Calcd for C₁₉H₃₁BN₂O₅×2HCl×2H₂O: C, 46.84; H,7.65; N, 5.75. Found C, 46.94; H, 7.58; N, 5.95.

Example 62: Preparation of2-amino-6-borono-2-(2-(4,5-dihydrothieno[2,3-c]pyridin-6(7H)-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4,5-dihydrothieno[2,3-c]pyridin-6(7H)-yl)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except4,5,6,7-tetrahydrothieno[2,3-c]pyridine is used as the amine in step 6.¹H NMR (D₂O, 500 MHz) δ 7.23 (d, J=5.0 Hz, 1H), 6.86 (d, J=5.0 Hz, 1H),[4.64 (d, J=14.0 Hz), 4.34 (d, J=14.0 Hz), 2H, AB system], 3.77-3.73 (m,1H), 3.55-3.37 (m, 2H), 3.34-3.26 (m, 1H), 2.99 (brs, 2H), 2.35-2.30 (m,2H), 1.88-0.93 (m, 1H), 1.76-1.82 (m, 1H), 1.29-1.39 (m, 3H), 1.12-1.19(m, 1H), 0.70 (t, J=7.0 Hz, 2H). ESI MS found for C₁₅H₂₅BN₂O₄S m/z[341.5 (M+1) 1%, 323.5 (M+1−18) 12%, 305.5 (M+1-2×18) 100%, 661.9 (2M−1−18) 4%, (339.5 (M−1) 34%, 321.5 (M−1−18) 100%].

Example 63: Preparation of2-amino-6-borono-2-(2-(3-(3,4-difluorophenyl)propylamino)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(3-(3,4-difluorophenyl)propylamino)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except3-(3,4-difluorophenyl)propan-1-amine is used as the amine in step 6. ¹HNMR (D₂O, 500 MHz) δ 7.13-7.00 (m, 2H), 6.95-6.89 (m, 1H), 3.20-3.05 (m,1H), 3.01-2.91 (m, 3H), 2.60 (t, J=8.0 Hz, 2H), 2.15 (t, J=8.0 Hz, 2H),1.96-1.73 (m, 4H), 1.36-1.25 (m, 3H), 1.22-1.06 (m, 1H), 0.68 (t, J=7.0Hz, 2H). ¹⁹F NMR −142.00 (d, J=22.0 Hz, 1F), −138.58 (d, J=22.0 Hz, 1F).ESI MS found for C₁₇H₂₇BF₂N₂O₄ m/z [355.6 (M+1−18) 20%, 337.6 (M+1-2×18)90%, 319.5 (M+1-3×18) 100%, 371.6 (M−1) 20%, 353.6 (M−1−18) 100%].

Example 64: Preparation of2-amino-6-borono-2-(2-(3-(2-chloro-5-(trifluoromethyl)phenyl)propylamino)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(3-(2-chloro-5(trifluoromethyl)phenyl)propylamino)ethyl) hexanoic acid dihydrochloridemonohydrate is prepared in a manner analogous to that set forth inExample 16, except 3-(2-chloro-5-(trifluoromethyl)phenyl)propan-1-amineis used as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 7.56 (s, 1H),7.48 (d, J=8.0 Hz, 1H), 7.44 (d, J=8.0 Hz, 1H), 3.19-3.13 (m, 1H), 3.01(t, J=8.0 Hz, 2H), 2.99-2.95 (m, 1H), 2.79 (t, J=8.0 Hz, 2H), 2.13 (t,J=8.0 Hz, 2H), 1.91 (tt, J=8.0, 8.0 Hz, 2H), 1.87-1.81 (m, 1H),1.75-1.69 (m, 1H), 1.33-1.25 (m, 3H), 1.15-1.08 (m, 1H), 0.66 (t, J=7.0Hz, 2H). ¹⁹F NMR −61.66 (s, 3F). ESI MS found for C₁₈H₂₇BClF₃N₂O₄ m/z[421.6/423.6 (M+1−18) 38%, 403.6/405.6 (M+1−2×18) 75%, 367.6(M+1-2×18-Cl⁻) 100%, 437.6/439.7 (M−1) 30%, 419.6/421.6 (M−1−18) 100%,383.6 (M−1−18-Cl⁻) 30%].

Example 65: Preparation of2-amino-6-borono-2-(2-(3-(3-methoxyphenyl)propylamino)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(3-(3-methoxyphenyl)propylamino)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except 3-(3-methoxyphenyl)propan-1-amineis used as the amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 7.16-7.13 (m,1H), 6.75-6.71 (m, 3H), 3.64 (s, 3H), 3.11-3.04 (m, 1H), 2.93-2.83 (m,3H), 2.53 (t, J=8.0 Hz, 2H), 2.06 (t, J=8.0 Hz, 2H), 1.85-1.75 (m, 3H),1.68-1.60 (m, 1H), 1.27-1.17 (m, 3H), 1.10-1.00 (m, 1H), 0.60 (t, J=8.0Hz, 2H). ESI MS found for C₁₈H₃BN₂O₅ m/z [389.7 (M+Na⁺) 5%, 331.6(M+1−2×18) 70%, 313.6 (M+1−3×18) 100%].

Example 66: Preparation of2-amino-6-borono-2-(2-(3-(2,4-dichlorophenyl)propylamino)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(3-(2,4-dichlorophenyl)propylamino)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 3-(2,4-dichlorophenyl)propan-1-amine is used asthe amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 7.24 (m, 1H), 7.06 (m, 2H),3.12-3.06 (m, 1H), 2.95-2.89 (m, 3H), 2.58 (t, J=8.0 Hz, 2H), 2.11 (t,J=8.0 Hz, 2H), 1.84-1.74 (m, 3H), 1.70-1.65 (m, 1H), 1.25-1.15 (m, 3H),1.10-1.00 (m, 1H), 0.56 (t, J=7.0 Hz, 2H). ¹³C NMR (D₂O) δ 23.24, 25.07,25.10, 29.00, 31.30, 35.05, 42.84, 47.52, 62.48, 125.78, 127.14, 128.84,131.25, 132.65, 133.84, 136.37, 172.94. ESI MS found for C₁₇H₂₇BCl₂N₂O₄m/z [387.5 (M+1−18) 20%, 369.5 (M+1−2×18) 100%, 385.5 (M−1−18) 100%].Anal. Calcd for C₁₇H₂₇BCl₂N₂O₄: C, 42.67; H, 6.06); N, 5.85). Found: C,42.53; H, 6.00; N, 5.68.

Example 67: Preparation of2-amino-6-borono-2-(2-(tert-butylamino)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(tert-butylamino)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except tert-butylamine is used as the amine instep 6. ¹H NMR (D₂O, 500 MHz) δ 3.11-3.05 (m, 1H), 2.89-2.83 (m, 1H),2.13-2.06 (m, 2H), 1.86-1.81 (m, 1H), 1.75-1.69 (m, 1H), 1.28-1.22 (m,3H), 1.17 (s, 9H), 1.09-1.02 (m, 1H), 0.61 (t, J=8.0 Hz, 2H). ESI MSfound for C₁₂H₂₇BN₂O₄ m/z [239.5 (M+1−2×18) 100%, 255.5 (M−1−18) 90%].

Example 68: Preparation of2-amino-6-borono-2-(2-(cyclopropylamino)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(cyclopropylamino)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except cyclopropanamine is used as the amine instep 6. ¹H NMR (D₂O, 500 MHz) δ 3.32-3.25 (m, 1H), 3.14-3.10 (m, 1H),2.69-2.63 (m, 1H), 2.25-2.16 (m, 2H), 1.90-1.86 (m, 1H), 1.80-1.75 (m,1H), 1.39-1.24 (m, 3H), 1.15-1.08 (m, 1H), 0.81-0.76 (m, 4H), 0.75-0.68(m, 2H). ESI MS found for C₁₁H₂₃BN₂O₄ m/z [223.4 (M+1−2×18) 30%, 205.4(M+1−3×18), 60%, 239.5 (M−1−18) 100%].

Example 69: Preparation of2-amino-6-borono-2-(2-(4-methoxybenzylamino)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(4-methoxybenzylamino)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except (4-methoxyphenyl)methanamine is used asthe amine in step 6. ¹H NMR (D₂O, 500 MHz) δ 7.28 (d, J=8.0 Hz, 2H),6.70 (d, J=8.0 Hz, 2H), 4.09 (d, J=14.0 Hz, 1H), 4.06 (d, J=14.0 Hz,1H), 3.69 (s, 3H), 3.19-3.14 (m, 1H), 3.02-2.96 (m, 1H), 2.16 (t, J=8.0Hz, 2H), 1.82-1.77 (m, 1H), 1.72-1.67 (m, 1H), 1.30-1.18 (m, 3H),1.10-1.02 (m, 1H), 0.61 (t, J=7.0 Hz, 2H). ESI MS found for C₁₆H₂₇BN₂O₅m/z [319.6 (M−1−18) 100%, 321.5 (M+1−18) 60%, 303.6 (M+1-2×18) 100%].

Example 70: Preparation of2-amino-2-(2-(benzylamino)ethyl)-6-boronohexanoic acid dihydrochloride

2-Amino-2-(2-(benzylamino)ethyl)-6-boronohexanoic acid dihydrochloridemonohydrate is prepared in a manner analogous to that set forth inExample 16, except benzylamine is used as the amine in step 6. ¹H NMR(D₂O, 500 MHz) δ 7.42-7.38 (m, 1H), 7.36-7.32 (m, 4H), 4.13 (s, 2H),3.23-3.17 (m, 1H), 3.05-2.99 (m, 1H), 2.18 (t, J=8.0 Hz, 2H), 1.88-1.78(m, 1H), 1.74-1.69 (m, 1H), 1.30-1.18 (m, 3H), 1.10-1.06 (m, 1H), 0.63(t, J=7.0 Hz, 2H). ESI MS found for C₁₅H₂₅BN₂O₄ m/z [273.5 (M+1−2×18)80%, 255.6 (M+1−3×18) 100%].

Example 71: Preparation of2-amino-6-borono-2-(2-((2-(dimethylamino)ethyl)(methyl)amino)ethyl)hexanoicacid trihydrochloride

2-Amino-6-borono-2-(2-((2-(dimethylamino)ethyl)(methyl)amino)ethyl)hexanoicacid trihydrochloride is prepared in a manner analogous to that setforth in Example 16, except N1,N1,N2-trimethylethane-1,2-diamine is usedas the amine in step 6. The final compound was isolated as thetrihydrochloride salt and monohydrate. ¹H NMR (D₂O, 500 MHz) δ 3.58-3.52(m, 4H), 3.45-3.39 (m, 1H), 3.27-3.22 (m, 1H), 2.89 (s, 9H), 2.33-2.23(m, 2H), 1.92-1.86 (m, 1H), 1.81-1.75 (m, 1H), 1.35-1.29 (m, 3H),1.18-1.13 (m, 1H), 0.70 (t, J=8.0 Hz, 2H). ESI MS found for C₁₃H₃₀BN₃O₄m/z [268.5 (M+1−2×18) 100%, 286.6 (M+1−18) 7%].

Example 72: Preparation of2-amino-6-borono-2-(2-(cyclopentylamino)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(cyclopentylamino)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except cyclopentanamine is used as the amine instep 6. ¹H NMR (D₂O, 500 MHz) δ 3.55-3.43 (m, 1H), 3.20-3.13 (m, 1H),3.03-2.92 (m, 1H), 2.21-2.15 (m, 2H), 2.01-1.92 (m, 2H), 1.90-1.82 (m,1H), 1.81-1.71 (m, 1H), 1.67-1.57 (m, 2H), 1.55-1.45 (m, 4H), 1.36-1.25(m, 3H), 1.18-1.08 (m, 1H), 0.60-0.71 (m, 2H). ESI MS found forC₁₃H₂₇BN₂O₄ m/z [251.5 (M+1-2×18) 100%, 233.5 (M+1−3×18) 70%].

Example 73: Preparation of2-amino-2-(2-((2-aminoethyl)(benzyl)amino)ethyl)-6-boronohexanoic acidtrihydrochloride

2-Amino-2-(2-((2-aminoethyl)(benzyl)amino)ethyl)-6-boronohexanoic acidtrihydrochloride is prepared in a manner analogous to that set forth inExample 16, except tert-butyl 2-(benzylamino)ethylcarbamate is used asthe amine in step 6. The final compound was isolated as thetrihydrochloride salt and monohydrate. ¹H NMR (D₂O, 500 MHz) δ 7.50-7.43(m, 5H), [4.52 (d, J=13.0 Hz, 1H), 4.22 (d, J=13.0 Hz, 1H), AB-system],3.56-3.50 (m, 1H), 3.46-3.37 (m, 4H), 3.24-3.19 (m, 1H), 2.31 (dt,J₁=16.0 Hz, J₂=8.0 Hz, 1H), 2.08-1.99 (m, 1H), 1.39-1.22 (m, 2H),1.14-1.04 (m, 3H), 1.01-0.91 (m, 1H), 0.57 (t, J=6.0 Hz, 2H). ESI MSfound for C₁₇H₃₀BN₃O₄ m/z [316.5 (M+1−2×18) 100%, 298.6 (M+1−3×18) 20%,332.6 (M−1−18) 100%].

Example 74: Preparation of2-amino-6-borono-2-(2-((4-isopropoxybenzyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-((4-isopropoxybenzyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except1-(4-isopropoxyphenyl)-N-methylmethanamine is used as the amine in step6. ¹H NMR (D₂O, 500 MHz) δ [7.36 (d, J=9.0 Hz, 2^(nd) rotamer), 2H, 7.34(d, J=9.0 Hz, 1^(st) rotamer)], 6.99 (d, J=9.0 Hz, 2H), 4.67-4.61 (m,1H), [4.30 (d, J=13.0 Hz, 1^(st) rotamer), 4.28 (d, J=13.0 Hz, 2^(nd)rotamer), 1H], [4.16 (d, J=13.0 Hz, 1^(st) conformer), 4.09 (d, J=13.0Hz, 2^(nd) conformer), 1H], 3.24-3.14 (m, 1H), [3.05-3.11 (m, 2^(nd)rotamer), 2.96-3.01 (m, 1^(st) rotamer), 1H], [2.78 (s, 1^(st) rotamer),2.73 (s, 2^(nd) rotamer), 3H], 2.31-2.21 (m, 1H), [2.15-2.09 (m, 2^(nd)rotamer), 2.04-1.96 (m, 1^(st) rotamer), 1H], 1.32-1.27 (m, 2H), 1.24(d, J=6.0 Hz, 6H), 1.20-1.06 (m, 3H), 1.01-0.93 (m, 1H), [0.66 (t, J=8.0Hz, 1^(st) rotamer), 0.58 (t, J=8.0 Hz, 2^(nd) rotamer), 2H]. ESI MSfound for C₁₉H₃₃BN₂O₅ m/z [363.6 (M+1−18) 70%, 345.5 (M+1−2×18) 100%].

Example 75: Preparation of2-amino-2-(2-(azetidin-1-yl)ethyl)-6-boronohexanoic acid dihydrochloride

2-Amino-2-(2-(azetidin-1-yl)ethyl)-6-boronohexanoic acid dihydrochloridemonohydrate is prepared in a manner analogous to that set forth inExample 16, except azetidine is used as the amine in step 6. ¹H NMR(D₂O, 500 MHz) δ 4.24-4.15 (m, 2H), 4.05-3.93 (m, 2H), 3.39-3.32 (m,1H), 3.22-3.13 (m, 1H), 2.54-2.41 (m, 1H), 2.39-2.29 (m, 1H), 2.00 (t,J=8.0 Hz, 2H), 1.88-1.80 (m, 1H), 1.77-1.67 (m, 1H), 1.36-1.23 (m, 3H),1.19-1.08 (m, 1H), 0.69 (t, J=7.0 Hz, 2H). ESI MS found for C₁₁H₂₃BN₂O₄m/z [241.5 (M+1−18) 7%, 223.4 (M+1−2×18) 100%].

Example 76: Preparation of2-amino-6-borono-2-(2-(4-phenylpiperazin-1-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(4-phenylpiperazin-1-yl)ethyl)hexanoic aciddihydrochloride monohydrate is prepared in a manner analogous to thatset forth in Example 16, except 1-phenylpiperazine is used as the aminein step 6. ¹H NMR (D₂O, 500 MHz) δ 7.31 (t, J=8.0 Hz, 2H), 7.04 (d,J=8.0 Hz, 2H), 7.00 (t, J=8.0 Hz, 1H), 3.44-3.20 (m, 8H), 3.13-3.03 (m,2H), 2.25-2.12 (m, 2H), 1.88-1.79 (m, 1H), 1.77-1.66 (m, 1H), 1.39-1.27(m, 3H), 1.19-1.11 (m, 1H), 0.71 (t, J=8.0 Hz, 2H). ESI MS found forC₁₈H₃₀BN₃O₄ m/z [344.5 (M−1-18) 100%, 328.6 (M+1-2×18) 100%].

Example 77: Preparation of2-amino-6-borono-2-(2-(4-(2-methoxyethyl)piperazin-1-yl)ethyl)hexanoicacid trihydrochloride

2-Amino-6-borono-2-(2-(4-(2-methoxyethyl)piperazin-1-yl)ethyl)hexanoicacid trihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except 1-(2-methoxyethyl)piperazine isused as the amine in step 6. ESI MS found for C₁₅H₃₂BN₃O₅ m/z [310.6(M+1-2×18) 89%, 328.6 (M+1−18) 3%, 326.6 (M−1−18) 13%].

Example 78: Preparation of2-amino-6-borono-2-(2-((2-hydroxy-2-phenylethyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-((2-hydroxy-2-phenylethyl)(methyl)amino)ethyl)hexanoicacid dihydrochloride monohydrate is prepared in a manner analogous tothat set forth in Example 16, except 2-(methylamino)-1-phenylethanol isused as the amine in step 6. ESI MS found for C₁₇H₂₉BN₂O₅ m/z [317.5,(M+1-2×18) 20%, 299.5 (M+1-3×18) 100%].

Example 79: Preparation of2-amino-6-borono-2-(piperidin-1-ylmethyl)hexanoic acid Step 1: diethyl2-(benzyloxycarbonylamino)-2-(but-3-enyl)malonate

A suspension of sodium hydride (510 mg, 21.24 mmol, 60% suspension) indimethylformaamide (30 mL) was treated with diethyl carbobenzyloxyprotected aminomalonate (6.0 g, 19.4 mmol) in dimethylformaamide (30 mL)at 0° C. After stirring for 30 minutes, bromobutene (2.89 g, 21.43 mmol,1.92 mL) was added and the resulting solution was warmed to 90° C. andstirred an additional 4 h. The reaction mixture was diluted with ethylacetate (200 mL) and washed successively with water (2×100 mL) andsaturated aqueous sodium chloride (1×100 mL). After evaporating theorganic layer to dryness the resulting residue was purified bycombiflash (80 g silica column, eluted with 15-50% ethyl acetate inheptanes) to give diethyl2-(benzyloxycarbonylamino)-2-(but-3-enyl)malonate (4.8 g, 67%). ¹H NMR(CDCl₃) δ 7.36 (m, 5H), 7.26-6.93 (m, 1H), 6.20 (bs, 1H), 5.75 (m, 1H),5.11 (s, 2H), 5.04-4.04 (m, 2H), 4.24 (m, 4H), 2.43 (m, 2H), 1.96-1.93(m, 2H), 1.27-1.21 (m, 6H). MS found for C₁₉H₂₅NO₆ m/z [364 (M+1)]

Step 2: 2-(benzyloxycarbonylamino)-2-(ethoxycarbonyl)hex-5-enoic acid

A solution of diethyl 2-(benzyloxycarbonylamino)-2-(but-3-enyl)malonate(4.8 g, 13.23 mmol) in ethanol (45 mL) was cooled to −30° C. and treatedwith an aqueous solution of potassium hydroxide (1.55 g, 27.76 mmol in15 mL water). After the addition was complete, the solution was warmedto 0° C. for 30 minutes followed by room temperature for 1 h. With thereaction complete, the mixture was acidified with AcOH (1.8 g) andextracted with ethyl acetate (1×50 mL). The aqueous layer was acidifiedto pH 3 with 3 N hydrochloric acid and extracted with ethyl acetate(2×50 mL). The combined organic layers were washed with saturatedaqueous sodium chloride (1×50 mL), dried over MgSO₄ and concentrated togive 2-(benzyloxycarbonylamino)-2-(ethoxycarbonyl)hex-5-enoic acid (3.0g, 68%). ¹H NMR (CDCl₃) δ 10.00 (bs, 1H), 7.37 (m, 5H), 7.26-6.93 (m,1H), 6.21 (bs, 1H), 5.76 (m, 1H), 5.94-5.22 (m, 4H), 4.27 (m, 2H) 2.43(m, 2H), 1.96-1.93 (m, 2H), 1.27-1.21 (m, 3H). MS found for C₁₇H₂₁NO₆m/z [336 (M+1)].

Step 3: ethyl 2-(benzyloxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate

A solution of 2-(benzyloxycarbonylamino)-2-(ethoxycarbonyl)hex-5-enoicacid (1.54 g, 4.6 mmol) and triethylamine (557 mg, 5.52 mmol, 0.76 mL)in tetrahydrofuran (10 mL) was cooled to −30° C. and treated with ethylchloroformate (522 mg, 4.82 mmol, 0.46 mL) and stirred for 30 minutes. Asolution of sodium borohydride (175 mg, 4.6 mmol) in water (2 mL) wasadded and the mixture was stirred for 30 minutes. Once the reaction wascomplete, 3 N hydrochloric acid (1 mL) was added and the mixture wasdiluted with ethyl acetate (50 mL), washed with water (1×50 mL) andextracted with ethyl acetate (1×50 mL). The combined organic layers wereconcentrated and purified using a combiflash system (2×12 g silica gelcolumn, eluting with 10-50% ethyl acetate in heptanes) to give ethyl2-(benzyloxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate (700 mg, 48%).¹H NMR (CDCl₃) δ 7.29 (m, 5H), 5.82 (bs, 1H), 5.68-5.62 (m, 1H), 5.03(s, 1H), 4.94-4.86 (m, 2H), 4.17 (m, 2H) 3.76 (dd, J=11.4 Hz, 1H), 1.97(m, 2H), 1.77 (m, 2H), 1.21 (t, J=7.2 Hz, 3H). MS found for C₁₇H₂₃NO₅m/z [322 (M+1)].

Step 4: 3-benzyl 4-ethyl4-(but-3-enyl)-2,2-dimethyloxazolidine-3,4-dicarboxylate

A solution of the ethyl2-(benzyloxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate 4 (820 mg, 2.55mmol) in toluene (10 mL) was treated with 2,2-dimethoxy propane (2 mL)and 4-toluenesulfonic acid (100 mg). The mixture was heated under refluxfor 1 h, cooled, concentrated and purified using a combiflash system (12g silica gel column, eluting with 5-50% of ethyl acetate in heptanes) togive 3-benzyl 4-ethyl4-(but-3-enyl)-2,2-dimethyloxazolidine-3,4-dicarboxylate (530 mg, 57%).¹H NMR (CDCl₃) δ 7.36 (m, 5H), 5.75 (m, 1H), 4.51 (m, 4H), 4.06 (m, 4H)2.08 (m, 4H), 1.65 (2 s, 6H), 1.13 (t, J=7.1 Hz, 3H). MS found forC₂₀H₂₇NO₅ m/z [332 (M+1)].

Step 5: 3-benzyl 4-ethyl2,2-dimethyl-4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)oxazolidine-3,4-dicarboxylate

While under an argon atmosphere, a solution ofchloro(1,5-cyclooctadiene) iridium(I) dimer (15 mg, 0.022 mmol) and1,2-bis(diphenyl-phosphino) ethane (18 mg, 0.044 mmol) indichloromethane (5 mL) was treated with pinacol borane (225 mg, 1.76mmol, 0.26 mL) and stirred for 15 minutes. To this mixture was added asolution of 3-benzyl 4-ethyl4-(but-3-enyl)-2,2-dimethyloxazolidine-3,4-dicarboxylate (530 mg, 1.47mmol) in dichloromethane (5 mL). After stirring for 19 h at roomtemperature the solution was concentrated and purified using acombiflash system (24 g column, eluting with 5-50% (ethyl acetate inheptanes) to give 3-benzyl 4-ethyl2,2-dimethyl-4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)oxazolidine-3,4-dicarboxylate(470 mg, 65%). ¹H NMR (CDCl₃) δ: 7.22 (m, 5H), 5.01 (m, 2H), 3.91 (m,4H), 2.20-2.01 (m, 1H), 1.75 (m, 1H), 1.51 (2s, 6H), 1.29 (m, 4H), 1.16(s, 12H), 1.02 (t, J=7.2 Hz, 3H), 0.69 (t, 2H). MS found for C₂₆H₄₀BNO₇m/z [490 (M+1), 522 (M+Na)].

Step 6: ethyl2-(benzyloxycarbonylamino)-2-(hydroxymethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

While under an argon atmosphere, a solution of 3-benzyl 4-ethyl2,2-dimethyl-4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)oxazolidine-3,4-dicarboxylate(350 mg, 0.72 mmol) in dichloromethane (5 mL) was cooled to −40° C. andcarefully treated with trimethylsilyltrifluoromethane sulfonate (1.09 g,4.29 mmol, 0.94 mL). After stirring for 30 minutes the solution waswarmed to 0° C. and stirred an additional 2 h, concentrated and purifiedusing a combiflash system (12 g silica gel column, eluting with 20-100%ethyl acetate in heptanes) to give ethyl2-(benzyloxycarbonylamino)-2-(hydroxymethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(180 mg, 56%). ¹HNMR (CDCl₃) δ 7.38-7.31 (m, 5H), 5.81 (bs, 1H), 5.10(s, 2H), 4.25-4.23 (m, 3H), 3.84 (d, 1H), 2.84 (m, 1H), 1.76-1.68 (m,1H), 1.41-1.35 (m, 2H), 1.28 (t, 3H), 1.23 (s, 12H), 1.11-1.03 (m, 1H),1.29 (m, 4H), 0.75 (t, 2H). MS found for C₂₃H₃₆BNO₇ m/z[450 (M+1)].

Step 7: ethyl2-(benzyloxycarbonylamino)-2-formyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

While under an argon atmosphere, a solution of oxalyl chloride (1.56 g,12.4 mmol, 0.98 mL) in dichloromethane (15 mL) was cooled to −78° C. andtreated with dimethyl sufoxide (1.94 g, 1.8 mL, 24.84 mmol) and stirredfor 10 minutes. To this mixture ethyl2-(benzyloxycarbonylamino)-2-(hydroxymethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(2.79 g, 6.21 mmol) in anhydrous dichloromethane (15 mL) was added andthe mixture was stirred for 30 minutes. The reaction mixture wasquenched by adding triethylamine (3.76 g, 5.2 mL, 37.26 mmol) at −78° C.and slowly warming the reaction mixture to room temperature. The mixturewas diluted with dichloromethane (25 mL) and washed successively withwater (2×25 mL) and saturated aqueous sodium chloride (25 mL). Organiclayer was dried over magnesium sulfate, filtered and evaporated todryness. The resulting residue was purified using a combiflash system(40 g column, eluted with 20-40% ethyl acetate in heptanes) to giveethyl2-(benzyloxycarbonylamino)-2-formyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(2.4 g, 86%). ¹H NMR (CDCl₃) δ: 9.49 (s, 1H), 7.28 (m, 5H), 5.85 (bs,1H), 5.03 (s, 2H), 4.17, 2.17-2.09 (m, 2H), 1.38-1.28 (m, 4H), 1.25-1.20(m, 5H), 1.19 (s, 12H), 0.68 (t, J=7.8 Hz, 2H). MS found for C₂₃H₃₄BNO₇m/z [47](M+Na)].

Step 8: ethyl2-(benzyloxycarbonylamino)-2-(piperidin-1-ylmethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of ethyl2-(benzyloxycarbonylamino)-2-formyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(0.503 g, 1.13 mmol), piperidine (0.39 mL, 4 mmol) and acetic acid (0.23mL, 4 mmol) in 1,2-dichloroethane (20 mL) was stirred for 15 minutesthen treated with sodium triacetoxyborohydride (0.85 g, 4 mmol). Afterstirring for 2 h at 65° C. the solution was cooled to room temperatureand concentrated. The resulting residue was purified using a combiflashsystem (12 g silica gel column, 10-100% ethyl acetate in heptanes) togive ethyl2-(benzyloxycarbonylamino)-2-(piperidin-1-ylmethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(300 mg, 52%). ¹H NMR (CDCl₃) δ: 7.36 (m, 5H), 6.05 (bs, 1H), 5.14 (d,1H), 5.03 (d, J=11.2 Hz, 1H), 4.19 (m, 2H), 3.06 (d, J=13.8 Hz, 1H,),2.59 (d, J=13.8 Hz, 1H), 2.34 (m, 4H), 2.15 (m, 1H), 1.78-1.70 (m, 1H),1.45-1.25 (m, 12H), 1.22 (s, 12H), 1.02 (m, 1H), 0.73 (t, J=7.8 Hz, 2H).MS found for C₂₈H₄₅BN₂O₇ m/z[517(M+1)].

Step 9: 2-amino-6-borono-2-(piperidin-1-ylmethyl)hexanoic aciddihydrochloride

A solution of ethyl2-(benzyloxycarbonylamino)-2-(piperidin-1-ylmethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(0.26 g, 0.51 mmol) in 6 N HCl (20 mL) was heated to a gentle reflux for48 h. After cooling to room temperature, the solution was washed withdichloromethane (5×15 mL) and concentrated (aqueous layer). Theresulting residue was dissolved in water (3 mL) and passed throughcation exchange resin Dowex 50-200 eluted with 2 N ammonia (4 g resinwas loaded on a column, washed successively with water, 1 N HCl, waterto neutral pH, 2 N ammonia solution and water to neutral pH). Fractionscontaining product were concentrated, diluted with minimal water,acidified with 6 N HCl, frozen and lyophilized to give2-amino-6-borono-2-(piperidin-1-ylmethyl)hexanoic acid dihydrochloride.(60 mg, 43%). ¹H NMR (D₂O) δ 3.64-3.53 (m, 1H), 3.34 (d, J=13.9 Hz, 1H),3.05-3.03 (m, 2H), 2.93-2.91 (m, 3H), 1.76-1.67 (m, 5H), 1.53-1.46 (m,3H), 1.31-1.30 (m, 3H), 1.09-1.07 (m, 1H), 0.70 (t, J=7.3 Hz, 2H). MSfound for C₁₂H₂₅BN₂O₄ m/z[254(M−18+1)].

Example 80: Preparation of2-amino-6-borono-2-((4-methylpiperazin-1-yl)methyl) hexanoic acidtrihydrochloride

2-Amino-6-borono-2-((4-methylpiperazin-1-yl)methyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 79, except 1-methylpiperazine is used as the amine in step 8.The final compound was isolated as the trihydrochloride salt. ¹HNMR(D₂O) δ 2.93 (d, J=14.2 Hz, 1H), 2.64 (bs 1H), 2.50 (d, J=14.3 Hz, 1H),2.33 (s, 3H), 1.77-1.65 (m, 1H), 1.50-1.43 (m, 1H), 1.33-1.30 (m, 3H),1.15-1.05 (m, 1H), 0.69 (t, J=8.2 Hz, 2H). MS found for C₁₂H₂₆BN₃O₄m/z[270(M−18+1)].

Example 81: Preparation of 2-amino-6-borono-2-(morpholinomethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(morpholinomethyl)hexanoic acid dihydrochloride isprepared in a manner analogous to that set forth in Example 79, exceptmorpholine is used as the amine in step 8. The final compound wasisolated as the dihydrochloride salt. ¹H NMR (D₂O) δ 3.65 (m, 4H), 2.95(d, J=14.3 Hz, 1H), 2.62-2.56 (m, 2H), 2.49 (d, J=14.4 Hz, 1H),2.47-2.41 (m, 2H), 1.80-1.70 (m, 1H), 1.54-1.47 (m, 1H), 1.34-1.32 (m,3H), 1.16-1.12 (m, 1H), 0.72 (t, J=8.1 Hz, 2H). MS found for C₁₂H₂₃BN₂O₅m/z[257.1 (M−18+1)].

Example 82: Preparation of 2-amino-6-borono-2-(hydroxymethyl)hexanoicacid hydrochloride

2-Amino-6-borono-2-(hydroxymethyl)hexanoic acid hydrochloride isprepared in a manner analogous to that set forth in Example 79, exceptin step 8 sodium borohydride is used instead of sodiumtriacetoxyborohydride and no amine is used. The final compound wasisolated as the hydrochloride salt. ¹HNMR (D₂O) δ 3.81 (d, J=12.0 Hz,1H), 3.55 (d, J=12.0 Hz, 1H), 1.73-1.52 (m, 2H), 1.39-1.06 (m, 4H), 0.67(t, J=7.4 Hz, 2H). MS found for C₇H₁₆BNO₅ m/z [188.1 (M−18+1)].

Example 83: Preparation of2-amino-6-borono-2-((propylamino)methyl)hexanoic acid dihydrochlorideStep 1: diethyl 2-(but-3-enyl)-2-(tert-butoxycarbonylamino)malonate

To a suspension of sodium hydride (8.7 g, 218 mmol, 60% suspension) indimethylformaamide (250 mL) at 0° C. was added diethyl2-(tert-butoxycarbonylamino)malonate (50.0 g, 182 mmol) indimethylformaamide (250 mL). After stirring for 30 minutes,4-bromobut-1-ene (29.5 g, 218 mmol, 22.2 mL) was added and the mixturewas warmed to 90° C. After stirring an additional 4 h, the solution wascooled to room temperature and the solvents were removed by evaporation.The resulting residue was diluted with ethyl acetate (1.0 L), washedsuccessively with water (2×250 mL), saturated aqueous sodium chloride(1×200 mL) and concentrated. Purification using a combiflash system (330g silica column, eluted with 15-50% ethyl acetate in heptanes) gavediethyl 2-(but-3-enyl)-2-(tert-butoxycarbonylamino)malonate (54 g, 90%).¹H NMR (CDCl₃) δ 5.92 (bs, 1H), 5.79-5.71 (m, 1H), 5.03-4.93 (m, 2H),4.24-4.19 (m, 4H), 2.36 (m, 2H), 1.96-1.93 (m, 2H), 1.42 (s, 9H),1.27-1.24 (m, 6H).

Step 2: 2-(tert-butoxycarbonylamino)-2-(ethoxycarbonyl)hex-5-enoic acid

A solution of the diethyl2-(but-3-enyl)-2-(tert-butoxycarbonylamino)malonate (10.0 g, 30.4 mmol)in ethanol (100 mL) was cooled to 0° C. and treated with aqueous sodiumhydroxide (1 N, 31 mL). After stirring for 30 minutes, the cooling bathwas removed and stirring was continued for an additional 19 h. Thesolvent was removed by evaporation and the resulting residue was dilutedwith water (150 mL) and washed with ethyl acetate (2×100 mL). Theaqueous layer was acidified with concentrated hydrochloric acid to pH 2and extracted with ethyl acetate (2×150 mL). The combined organic layerswere washed with saturated aqueous sodium chloride (1×100 mL), driedover MgSO₄, filtered and concentrated to give2-(tert-butoxycarbonylamino)-2-(ethoxycarbonyl)hex-5-enoic acid (8.2 g,82%). ¹H NMR (CDCl₃) δ 5.87-5.75 (m, 1H), 5.06-5.02 (m, 2H), 4.26 (m,2H), 2.34 (m, 2H), 1.96-1.93 (m, 2H), 1.43 (s, 9H), 1.29 (m, 3H).

Step 3: ethyl 2-(tert-butoxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate

A solution of the2-(tert-butoxycarbonylamino)-2-(ethoxycarbonyl)hex-5-enoic acid (7.5 g,24.9 mmol) and triethylamine (3.01 g, 29.9 mmol, 4.15 mL) in THF (10 mL)was cooled to −40° C. and treated with ethyl chloroformate (2.97 g, 27.4mmol, 2.65 mL). After stirring for 30 minutes, the precipitate(triethylamine hydrochloride) was removed by filtration and the filtratewas collected and cooled to −40° C. A solution of sodiumborohydride (950mg, 24.9 mmol) in water (10 mL) was added and the resulting solution wasstirred for 30 minutes. After quenching the reaction mixture with 3 Nhydrochloric acid (5 mL), the mixture was diluted with ethyl acetate(150 mL), washed with water (1×50 mL) and extracted with ethyl acetate(1×150 mL). The combined organic layers were concentrated, dried overMgSO₄, filtered and purified using a combiflash system (80 g silica gelcolumn, eluting with 10-50% ethyl acetate in heptanes) to give ethyl2-(tert-butoxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate (5.6 g, 78%).¹H NMR (CDCl₃) δ 5.71-5.62 (m, 1H), 5.52 (bs, 1H), 4.96-4.87 (m, 2H),4.20-4.12 (m, 2H) 4.07-4.03 (m, 2H), 3.73 (d, J=12.0 Hz, 1H), 2.22-1.62(m, 4H), 1.37 (m, 9H), 1.22 (t, J=7.2 Hz, 3H).

Step 4: ethyl 2-(acetoxymethyl)-2-(tert-butoxycarbonylamino)hex-5-enoate

A solution of the ethyl2-(tert-butoxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate (10.0 g, 35mmol) and dimethylaminopyridine (4.48 g, 35 mmol) in dichloromethane(100 mL) was treated with acetic anhydride and stirred at roomtemperature overnight. The solution was concentrated and the resultingresidue purified using a combiflash system (89 g column, eluting with20-50% ethyl acetate in heptanes) to give ethyl2-(acetoxymethyl)-2-(tert-butoxycarbonylamino)hex-5-enoate (10 g, 80%).¹H NMR (CDCl₃) δ 5.78-5.68 (m, 1H), 5.55 (bs, 1H), 5.03-4.93 (m, 2H),4.73 (d, J=11.0 Hz, 1H) 4.32 (d, J=11.0 Hz, 1H,), 4.20 (q, J=7.2 Hz,2H), 2.36 (m, 1H), 2.07-2.05 (m, 1H), 2.02 (s, 3H), 1.89-1.75 (m, 2H),1.43 (m, 9H), 1.27 (t, J=7.2 Hz, 3H). MS found for C₁₆H₂₇NO₆m/z[330(M+1)].

Step 5: ethyl2-(acetoxymethyl)-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

While under an argon atmosphere, a solution ofchloro(1,5-cyclooctadiene)iridium(I) dimer (160 mg, 0.23 mmol) and1,2-bis(diphenyl-phosphino) ethane (190 mg, 0.48 mmol) indichloromethane (50 mL) was treated with pinacol borane (7.78 g, 61mmol, 8.8 mL) and stirred for 15 minutes. To this mixture was added asolution of ethyl2-(acetoxymethyl)-2-(tert-butoxycarbonylamino)hex-5-enoate (10 g, 30.4mmol) in dichloromethane (50 mL). After stirring for 19 h at roomtemperature the solution was concentrated and purified using acombiflash system (120 g column, eluting with 5-50% ethyl acetate inheptanes) to give ethyl2-(acetoxymethyl)-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(7.5 g, 54%). ¹H NMR (CDCl₃) δ 5.49 (bs, 1H), 4.72 (d, 1H), 4.33 (d,1H), 4.23 (q, 2H), 2.18 (m, 1H), 2.01 (s, 3H), 1.69 (m, 2H), 1.43 (s,9H), 1.29 (m, 4H), 1.23 (s, 12H), 0.88 (t, 3H), 0.74 (t, 2H). MS foundfor C₂₂H₄₀BNO₈ m/z [480(M+Na)].

Step 6: ethyl2-(tert-butoxycarbonylamino)-2-(hydroxymethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of ethyl2-(acetoxymethyl)-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(12.0 g, 26.3 mmol) in ethanol (100 mL) was treated with solid potassiumcarbonate (3.62 g, 26.3 mmol) and stirred for 2 h. The solution wasfiltered and the filtrate was evaporated to dryness. The resultingresidue was dissolved in ethyl acetate (150 mL) and washed successivelywith water (50 mL) and saturated aqueous sodium chloride (50 mL).Organic layer was concentrated and purified using a combiflash system(120 g column, eluting with 20-30% ethyl acetate in heptanes) to giveethyl2-(tert-butoxycarbonylamino)-2-(hydroxymethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(7.0 g, 78%). ¹H NMR (CDCl₃) δ 5.25 (bs, 1H), 4.00 (m, 2H), 3.91 (d,J=11.3 Hz, 1H), 3.60 (d, J=11.3 Hz, 1H), 1.53-1.46 (m, 1H), 1.23 (s,9H), 1.21-1.15 (m, 1H), 1.06 (m, 7H), 1.03 (s, 12H), 0.90 (m, 1H), 0.54(t, J=7.8 Hz, 2H). MS found for C₂₀H₃₈BNO₇ m/z[438(M+Na)]

Step 7: ethyl2-(tert-butoxycarbonylamino)-2-formyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

While under an argon atmosphere, a solution of oxalyl chloride (1.46 g,0.88 mL, 11.6 mmol) in dichloromethane (15 mL) was cooled to −78° C. andtreated with dimethyl sulfoxide (1.8 g, 1.64 mL, 23.2 mmol) and stirredfor 10 minutes. To this mixture ethyl2-(tert-butoxycarbonylamino)-2-(hydroxymethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(2.4 g, 5.78 mmol) in anhydrous dichloromethane (15 mL) was added andthe mixture was stirred for 30 minutes. The reaction mixture wasquenched by adding triethylamine (3.5 g, 4.8 mL, 34.7 mmol) at −78° C.and slowly warming the reaction mixture to room temperature. The mixturewas diluted with dichloromethane (25 mL) and washed successively withwater (2×25 mL) and saturated aqueous sodium chloride (25 mL). Organiclayer was dried over magnesium sulfate, filtered and evaporated todryness. The resulting residue was purified using a combiflash system(40 g column, eluted with 20-40% ethyl acetate in heptanes) to giveethyl2-(tert-butoxycarbonylamino)-2-formyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(1.35 g, 57%). ¹HNMR (CDCl₃) δ 9.58 (s, 1H), 5.64 (bs, 1H), 4.25 (m,2H), 2.13 (m, 2H), 1.45 (m, 9H), 1.28 (m, 4H), 1.24 (s, 12H), 0.88 (t,J=6.4 Hz, 3H), 0.77 (t, J=7.9 Hz, 2H). MS found for C₂₀H₃₆BNO₇m/z[436(M+Na)].

Step 8: ethyl2-(tert-butoxycarbonylamino)-2-((propylamino)methyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A slurry of ethyl2-(tert-butoxycarbonylamino)-2-formyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(172 mg, 0.42 mmol) and propylamine (40 μL, 0.49 mmol, 1.3 equiv) in1,2-dichloroethane (3 mL) was treated with sodium triacetoxyborohydride(352 mg, 1.66 mmol, 4 equiv). Acetic acid (2 drops, ca 3-5 equiv) wasadded and the mixture stirred at room temperature for 17 hours then 60°C. for 1 hour. Once the reaction was complete, saturated aqueous sodiumbicarbonate was added and the solution was extracted withdichloromethane. The organic extracts were washed with saturated aqueousNaCl, dried over MgSO₄, filtered and concentrated. Purification by flashchromatography (0-60% ethyl acetate in hexane) gave ethyl2-(tert-butoxycarbonylamino)-2-((propylamino)methyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas an oil (66 mg, 34%). ¹H NMR (CDCl₃, 400 MHz) δ 4.16 (m, 2H), 3.5-3.3(m, 2H), 3.2 (br m, 2H), 2.9 (m, 1H), 1.8-1.6 (m, 4H), 1.5-1.4 (m, 2H),1.38 (s, 9H), 1.36-1.3 (m, 3H), 1.22 (t, J=7.2 Hz, 3H), 1.18 (s, 12H),1.05 (m, 1H), 0.75 (t, J=7.4 Hz, 3H), 0.68 (t, J=7.5 Hz, 2H). ESI MS:obsd m/z 457 (M+H)⁺.

Step 9: 2-amino-6-borono-2-((propylamino)methyl)hexanoic acid

A solution of ethyl2-(tert-butoxycarbonylamino)-2-((propylamino)methyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(66 mg, 0.14 mmol) in 6 N HCl (5 mL) and 1,4-dioxane (1 mL) was heatedat 100° C. for 16 hrs. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (6×25 mL). The aqueouslayer was frozen (dry ice/acetone) and lyophilized to give2-amino-6-borono-2-((propylamino)methyl)hexanoic acid as adihydrochloride salt (40 mg). ¹H NMR (D₂O, 400 MHz) δ 3.33 (d_(AB),J_(AB)=13.7 Hz, 1H), 3.21 (d_(AB), J_(AB)=13.7 Hz, 1H), 2.91-2.78 (m,2H), 1.88-1.75 (m, 1H), 1.70-1.60 (m, 1H), 1.54-1.38 (m, 2H), 1.24-1.08(m, 3H), 1.05-0.92 (m, 1H), 0.75-0.61 (m, 3H), 0.55-0.45 (m, 2H). ESI⁺MS: obsd m/z 229.1 (M−18H)⁺, 211.1 (M−36+H)⁺, ESI− MS: 227.1 (M−18−1)⁻.

Example 84: Preparation of2-amino-2-((benzylamino)methyl)-6-boronohexanoic acid

2-Amino-2-((benzylamino)methyl)-6-boronohexanoic acid dihydrochloride isprepared in a manner analogous to that set forth in Example 83, exceptbenzylamine is used as the amine in step 8. The final compound wasisolated as the dihydrochloride salt. ¹H NMR (D₂O, 400 MHz) δ 7.47-7.27(m, 5H), 3.85 (d_(AB), J_(AB)=13.4 Hz, 1H), 3.80 (d_(AB), J_(AB)=13.4Hz, 1H), 3.05 (d_(AB), J_(AB)=13.2 Hz, 1H), 2.69 (d_(AB), J_(AB)=13.2Hz, 1H), 1.76-1.64 (m, 1H), 1.58-1.46 (m, 1H), 1.37-1.18 (m, 3H),1.17-1.02 (m, 1H), 0.68 (t, J=7.8 Hz, 2H). ESI⁺ MS: obsd m/z 277.1(M−18+H)⁺, 259.1 (M−36+H)⁺, ESI− MS: 275.1 (M−18−1)⁻.

Example 85: Preparation of2-amino-6-borono-2-(((R)-2-hydroxypropylamino)methyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(((R)-2-hydroxypropylamino)methyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 83, except (R)-1-aminopropan-2-ol is used as the amine in step8. The final compound was isolated as the dihydrochloride salt. ¹H NMR(D₂O, 400 MHz) δ 3.89-3.80 (m, 1H), 3.70-3.40 (m, 4H), 3.31 (d_(AB),J_(AB)=12.7 Hz, 1H), 2.05-1.93 (m, 1H), 1.87-1.74 (m, 1H), 1.48-1.35 (m,3H), 1.33-1.18 (m, 3H), 0.77 (t, J=7.8 Hz, 2H). ESI⁺ MS: obsd m/z 227.1(M−36+H)⁺, 243.1 (M−18−1)⁻.

Example 86: Preparation of2-amino-6-borono-2-((butylamino)methyl)hexanoic acid dihydrochloride

2-Amino-6-borono-2-((butylamino)methyl)hexanoic acid dihydrochloride isprepared in a manner analogous to that set forth in Example 83, exceptbutan-1-amine is used as the amine in step 8. The final compound wasisolated as the dihydrochloride salt. ¹H NMR (D₂O, 400 MHz) δ 3.38(d_(AB), J_(AB)=13.8 Hz, 1H), 3.24 (d_(AB), J_(AB)=13.8 Hz, 1H),3.10-2.94 (m, 2H), 1.92-1.82 (m, 1H), 1.75-1.65 (m, 1H), 1.65-1.53 (m,2H), 1.40-1.21 (m, 4H), 1.22-1.1.08 (m, 1H), 0.68 (t, J=7.2 Hz, 2H).ESI⁺ MS: obsd m/z 243.1 (M−18+H)⁺, 225.1 (M−36+H)⁺, ESI− MS: 241.1(M−18−1).

Example 87: Preparation of2-amino-6-borono-2-((tetrahydro-2H-pyran-4-ylamino)methyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-((tetrahydro-2H-pyran-4-ylamino)methyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 83, except tetrahydro-2H-pyran-4-amine is used as the amine instep 8. The final compound was isolated as the dihydrochloride salt. ¹HNMR (D₂O, 400 MHz) δ 4.02-3.92 (m, 2H), 3.48-3.28 (m, 5H), 2.03-1.82 (m,3H), 1.75-1.58 (m, 3H), 1.38-1.26 (m, 3H), 1.20-1.10 (m, 1H), 0.68 (t,J=7.2 Hz, 2H). ESI⁺ MS: obsd m/z 271.1 (M−18+H)⁺, 253.1 (M−36+H)⁺, ESI−MS: 269.1 (M−18−1)⁻.

Example 88: Preparation of2-amino-6-borono-2-(((S)-1-hydroxy-4-methylpentan-2-ylamino)methyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(((S)-1-hydroxy-4-methylpentan-2-ylamino)methyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 83, except (R)-2-amino-4-methylpentan-1-ol is used as theamine in step 8. The final compound was isolated as the dihydrochloridesalt. ¹H NMR (D₂O, 400 MHz) δ 3.87-3.70 (m, 1H), 3.65-3.48 (m, 1H),3.46-3.40 (m, 1H), 3.39-3.33 (m, 1H), 3.33-3.27 (m, 1H), 3.24 (d_(AB),J_(AB)=13.8 Hz, 1H), 1.95-1.85 (m, 1H), 1.77-1.65 (m, 1H), 1.62-1.52 (m,1H), 1.50-1.40 (m, 2H), 1.39-1.27 (m, 3H), 1.20-1.08 (m, 1H), 0.86-0.78(m, 6H), 0.68 (t, J=7.4 Hz, 2H). ESI⁺ MS: obsd m/z 269.1 (M−36+H)⁺,285.1 (M−18−1)⁻.

Example 89: Preparation of2-amino-6-borono-2-(((1R,2S)-2-hydroxy-1,2-diphenylethylamino)methyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(((1R,2S)-2-hydroxy-1,2-diphenylethylamino)methyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 83, except (1S,2R)-2-amino-1,2-diphenylethanol is used as theamine in step 8. The final compound was isolated as the dihydrochloridesalt. ¹H NMR (D₂O, 400 MHz) δ 7.46-7.00 (m, 10H), 5.37-5.04 (m, 1H),4.57-4.46 (m, 1H), 3.35-2.85 (m, 2H), 1.96-1.82 (m, 1H), 1.76-1.60 (m,1H), 1.56-1.44 (m, 1H), 1.39-1.26 (m, 2H), 1.26-0.87 (m, 2H), 0.74-0.56(m, 2H). ESI⁺ MS: obsd m/z 383.1 (M−18+H)⁺, 365.1 (M−36+H)⁺, ESI− MS:381.1 (M−18−1)⁻.

Example 90: Preparation of2-amino-6-borono-2-(((S)-1-phenylethylamino)methyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(((S)-1-phenylethylamino)methyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 83, except (S)-1-phenylethanamine is used as the amine in step8. The final compound was isolated as the dihydrochloride salt. ¹H NMR(D₂O, 400 MHz) δ 7.48-7.32 (m, 5H), 4.50-4.37 (m, 1H), 3.30-3.12 (m,1H), 3.08-2.98 (m, 1H), 1.92-1.70 (m, 1H), 1.68-1.54 (m, 4H), 1.37-1.17(m, 3H), 1.18-0.96 (m, 1H), 0.73-0.55 (m, 2H). ESI⁺ MS: obsd m/z 291.1(M−18+H)⁺.

Example 91: Preparation of2-amino-6-borono-2-(((R)-1-hydroxypropan-2-ylamino)methyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(((R)-1-hydroxypropan-2-ylamino)methyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 83, except (R)-2-aminopropan-1-ol is used as the amine in step8. The final compound was isolated as the dihydrochloride salt. ¹H NMR(D₂O, 400 MHz) δ 4.07-3.87 (m, 2H), 3.80-3.71 (m, 1H), 3.51-3.27 (m,2H), 3.17-3.02 (m, 1H), 2.99-2.80 (m, 1H), 1.95-1.81 (m, 1H), 1.79-1.65(m, 1H), 1.45-1.35 (m, 1H), 1.32-1.18 (m, 2H), 1.15-0.90 (m, 3H), 0.61(t, J=7.2 Hz, 2H). ESI⁺ MS: obsd m/z 227.1 (M−36+H)⁺.

Example 92: Preparation of2-amino-6-borono-2-(2-(4-chlorophenoxy)ethyl)hexanoic acid hydrochlorideStep 1: tert-butyl4-(4-chlorophenoxy)-2-(diphenylmethyleneamino)butanoate

While under a nitrogen atmosphere, a solution of(benzhydrylidene-amino)-acetic acid tert-butyl ester (400 mg, 1.35 mmol)in tetrahydrofuran (7 mL) was cooled to −78° C. and treated with sodiumbis(trimethylsilyl)amide (1.49 mL, 1.0 M in tetrahydrofuran, 1.49 mmol)in a dropwise manner. After the addition was complete, stirring wascontinued for 30 minutes and 1-(2-bromoethoxy)-4-chlorobenzene (398 mg,1.69 mmol) was slowly added to the reaction mixture. Stirring wascontinued for 2 more hours, then slowly warmed to room temperatureovernight. The resulting solution was poured into water, and extractedwith ethyl acetate (3×). The combined organic phase was washed withsaturated aqueous sodium chloride, dried over anhydrous magnesiumsulfate, filtered and concentrated. Purification by flash columnchromatography (silica gel, 0-20% ethyl acetate in heptane) gavetert-butyl 4-(4-chlorophenoxy)-2-(diphenylmethyleneamino)butanoate as acolorless oil (450 mg. 74%); MS (+CI): m/z for C₂₇H₂₈ClNO₃: expected449.2. found 450.2 (M+H)⁺, 394.2 (M+H-isobutene)⁺.

Step 2: tert-butyl2-(2-(4-chlorophenoxy)ethyl)-2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

While under a nitrogen atmosphere, a solution of tert-butyl4-(4-chlorophenoxy)-2-(diphenylmethyleneamino)butanoate (450 mg, 1.0mmol) in tetrahydrofuran (7 mL) was cooled to −78° C. and treated withsodium bis(trimethylsilyl)amide (2.0 mL, 1.0 M in tetrahydrofuran, 2.0mmol) in a dropwise manner. After the addition was complete, stirringwas continued for 30 minutes and2-(4-iodobutyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (931 mg, 3.0mmol) was slowly added to the reaction mixture. Stirring was continuedfor 2 more hours, and then slowly warmed to room temperature overnight.The resulting solution was poured into water, and extracted with ethylacetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated. Purification by flash column chromatography(silica gel, 0-15% ethyl acetate in heptane) gave tert-butyl2-(2-(4-chlorophenoxy)ethyl)-2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas a colorless oil (486 mg. 77%); ¹H NMR (CDCl₃, 300 MHz) δ_(H) 7.54 (d,J=7 Hz, 2H), 7.36 (m, 4H), 7.18-7.32 (m, 6H), 6.82 (d, J=9 Hz, 2H), 4.19(m, 1H), 4.04 (m, 1H), 2.39 (ddd, J₁=14 Hz, J₂=9.5 Hz, J₃=5.0 Hz, 1H),2.22 (ddd, J₁=13.5 Hz, J₂=9.5 Hz, J₃=5.0 Hz, 1H), 1.73 (m, 2H),1.14-1.46 (m, 4H), 1.34 (s, 9H), 1.18 (s, 12H) and 0.76 (t, J=7 Hz, 2H);MS (+CI): m/z for C₃₇H₄₇BClNO₅: expected 631.3. found 632.3 (M+H)⁺,576.3 (M+H-isobutene)⁺.

Step 3: 2-amino-6-borono-2-(2-(4-chlorophenoxy)ethyl)hexanoic acid

A solution of2-(benzhydrylidene-amino)-2-[2-(4-chlorophenoxy)-ethyl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-hexanoicacid tert-butyl ester (486 mg) in 6 N HCl (6 ml) was warmed to 60° C.and stirred overnight. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (6 ml) and washed with dichloromethane (3×). The aqueous layer wasfrozen in liquid nitrogen and lyophilized to give2-amino-6-borono-2-(2-(4-chlorophenoxy)ethyl)hexanoic acidhydrochloride, as a colorless foam (125 mg, 85%); ¹H NMR (D⁴-MeOH, 300MHz) δ_(H) 7.24 (2H, d, J=7 Hz, 2H), 6.94 (d, J=7 Hz, 2H), 4.18 (m, 2H),2.52 (m, 1H), 2.46 (m, 1H), 1.92 (m, 2H), 1.22-1.52 (m, 4H) and 0.82 (t,J=7 Hz, 2H,); MS (+CI): m/z for C₁₄H₂₁BClNO₅: expected 329.1. found330.2 (M+H)⁺, 312.2 (M+H−H₂O)⁺, 659.4 (2 M+H)⁺, 641.4 (2 M+H−H₂O)⁺.

Example 93: Preparation of2-amino-6-borono-2-(2-(4-methoxyphenoxy)ethyl)hexanoic acidhydrochloride

2-Amino-6-borono-2-(2-(4-methoxyphenoxy)ethyl)hexanoic acidhydrochloride is prepared in a manner analogous to that set forth inExample 92, except 1-(2-bromoethoxy)-4-methoxybenzene is used as thealkylating agent in step 1. ¹H NMR (D⁴-MeOH, 300 MHz) δ 6.91 (d, J=9 Hz,2H), 6.85 (d, J=7 Hz, 2H), 4.12 (m, 2H), 3.74 (s, 3H), 2.46 (m, 1H),2.34 (m, 1H), 1.96 (m, 2H), 1.22-1.66 (m, 4H) and 0.84 (t, J=7 Hz, 2H);MS (+CI): m/z for C₁₅H₂₄BClNO₅: expected 325.2. found 326.2 (M+H)⁺,308.2 (M+H−H₂O)⁺.

Example 94: Preparation of2-Amino-6-borono-2-[2-(2,4-dichlorophenoxy)-ethyl]-hexanoic acidhydrochloride

2-Amino-6-borono-2-[2-(2,4-dichlorophenoxy)-ethyl]-hexanoic acid isprepared in a manner analogous to that set forth in Example 92, except1-(2-bromoethoxy)-2,4-dichlorobenzene is used as the alkylating agent instep 1. ¹H NMR (D⁴-MeOH, 300 MHz) δ 7.43 (d, J=2 Hz, 1H), 7.29 (dd,J₁=9.0 Hz, J₂=2.0 Hz, 1H), 7.09 (d, J=9 Hz, 1H), 4.30 (m, 1H), 4.21 (m,1H), 2.53 (ddd. J₁=15.5 Hz, J₂=7.5 Hz, J₃=4.5 Hz, 1H), 2.44 (ddd.J₁=15.5 Hz, J₂=7.0 Hz, J₃=4.5 Hz, 1H), 2.01 (m, 2H), 1.46 (m, 3H), 1.32(m, 1H) and 0.82 (t, J=7 Hz, 2H); MS (+CI): m/z for C₁₄H₂₀BCl₂NO₅:expected 363.1. found 364.2 (M+H)⁺, 346.2 (M+H—H₂O)⁺.

Example 95: Preparation of2-Amino-6-borono-2-[2-(3-trifluoromethylphenoxy)-ethyl]-hexanoic acidhydrochloride

2-Amino-6-borono-2-[2-(3-trifluoromethylphenoxy)-ethyl]-hexanoic acidhydrochloride is prepared in a manner analogous to that set forth inExample 92, except 1-(2-bromoethoxy)-3-(trifluoromethyl)benzene is usedas the alkylating agent in step 1. ¹H NMR (D⁴-MeOH, 300 MHz) δ 7.49 (t,J=8 Hz, 1H), 7.26 (m, 3H), 4.24 (m, 2H), 2.52 (m, 1H), 2.37 (m, 1H),1.96 (m, 2H), 1.46 (m, 3H), 1.32 (m, 1H) and 0.83 (t, J=7 Hz, 2H); MS(+CI): m/z for C₁₅H₂₁BF₃NO₅: expected 363.21. found 364.2 (M+H)⁺, 346.2(M+H−H₂O)⁺, 727.4 (2 M+H)⁺, 709.4 (2M+H−H₂O)⁺.

Example 96: Preparation of2-Amino-6-borono-2-[3-(4-chlorophenoxy)-propyl]-hexanoic acidhydrochloride

2-Amino-6-borono-2-[3-(4-chlorophenoxy)-propyl]-hexanoic acidhydrochloride is prepared in a manner analogous to that set forth inExample 92, except 1-(4-bromopropoxy)-4-chlorobenzene is used as thealkylating agent in step 1. ¹H NMR (D⁴-MeOH, 300 MHz) δ 7.24 (d, J=9 Hz,2H), 6.90 (d, J=9 Hz, 2H), 3.98 (m, 2H), 1.68-2.19 (m, 6H), 1.44 (m,3H), 1.27 (m, 1H) and 0.82 (t, J=7 Hz, 2H); MS (+CI): m/z forC₁₅H₂₃BClNO₅: expected 343.1. found 344.2 (M+H)⁺, 326.2 (M+H−H₂O)⁺.

Example 97: Preparation of 2-Amino-6-borono-2-methylhexanoic acidhydrochloride

2-Amino-6-borono-2-methylhexanoic acid hydrochloride is prepared in amanner analogous to that set forth in Example 92, except methyliodide isused as the alkylating agent in step 1. ¹H NMR (D₂O, 300 MHz) δ1.89-1.82 (m, 1H), 1.79-1.68 (m, 1H), 1.48 (s, 3H), 1.47-1.25 (m, 3H),1.22-1.13 (m, 1H), 0.69 (t, J=6.6 Hz, 2H). ESI MS found for C₇H₁₆BNO₄m/z [190.1 (M+1)].

Example 98: Preparation of 2-amino-6-borono-2-(3-fluorobenzyl)hexanoicacid hydrochloride

2-amino-6-borono-2-(3-fluorobenzyl)hexanoic acid hydrochloride isprepared in a manner analogous to that set forth in Example 92, except1-(bromomethyl)-3-fluorobenzene is used as the alkylating agent instep 1. ¹H NMR (CD₃OD, 300 MHz) δ 7.41-7.32 (m, 1H), 7.14-7.02 (m, 3H),3.33 (d_(AB), J=14.4 Hz, 1H), 3.14 (d_(AB), J=14.4 Hz, 1H), 2.10-1.80(m, 2H), 1.48-1.25 (m, 4H), 0.79 (t, J=6.9 Hz, 2H). ESI MS found forC₁₃H₁₉BFNO₄ m/z [284.2 (M+1)].

Example 99: Preparation of 2-amino-2-benzyl-6-boronohexanoic acidhydrochloride

2-amino-2-benzyl-6-boronohexanoic acid hydrochloride is prepared in amanner analogous to that set forth in Example 92, except benzyl bromideis used as the alkylating agent in step 1. ¹H NMR (D₂O, 300 MHz) δ7.32-7.21 (m, 3H), 7.24-7.24 (m, 2H), 3.27 (d_(AB), J=12.8 Hz, 1H), 3.04(d_(AB), J=12.8 Hz, 1H), 2.03-1.92 (m, 1H), 1.84-1.75 (m, 1H), 1.40-1.08(m, 4H), 0.68 (t, J=7.2 Hz, 2H). ESI MS found for C₁₃H₂₀BNO₄ m/z [266.1(M+1)].

Example 100: Preparation of 2-amino-6-borono-2-(3-methoxypropyl)hexanoicacid hydrochloride

2-Amino-6-borono-2-(3-methoxypropyl)hexanoic acid hydrochloride isprepared in a manner analogous to that set forth in Example 92, except1-bromo-3-methoxypropane is used as the alkylating agent in step 1. ¹HNMR (D₂O, 300 MHz) δ 3.29 (t, J=6.6 Hz, 2H), 3.13 (s, 3H), 1.90-1.62 (m,4H), 1.58-1.42 (m, 1H), 1.42-1.29 (m, 1H), 1.28-1.14 (m, 3H), 1.11-0.97(m, 1H), 0.58 (t, J=7.5 Hz, 2H). ESI MS found for C₁₀H₂₂BNO₅ m/z [248.1(M+1)].

Example 101: Preparation of 2-amino-6-borono-2-(3-hydroxypropyl)hexanoicacid hydrochloride

2-Amino-6-borono-2-(3-hydroxypropyl)hexanoic acid hydrochloride isprepared in a manner analogous to that set forth in Example 92, except2-(3-bromopropoxy)tetrahydro-2H-pyran is used as the alkylating agent instep 1. ¹H NMR (D₂O, 300 MHz) δ 3.42 (t, J=6.3 Hz, 2H), 1.96-1.64 (m,4H), 1.55-1.41 (m, 1H), 1.40-1.19 (m, 4H), 1.11-0.96 (m, 1H), 0.60 (t,J=7.5 Hz, 2H). ESI MS found for C₉H₂₀BNO₅ m/z [234.1 (M+1)].

Example 102: Preparation of2-((1H-imidazol-5-yl)methyl)-2-amino-6-boronohexanoic aciddihydrochloride

A solution of N-(diphenylmethylene)histidine (1-trityl) tert-butyl ester(400 mg, 0.65 mmol) in freshly distilled THF (4 mL) was cooled to −78°C. (under argon atmosphere) and treated with lithiumbis(trimethylsilyl)amide (1.5 mmol, 1.5 mL, 1.0 M in THF).2-(4-iodobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (401 mg, 1.30mmol) was added in one portion and the reaction was warmed to 50° C. andheated for 8 h. After being complete by TLC, the reaction mixture wascooled to 0° C., diluted with ethyl acetate and washed successively withsaturated aqueous NaHCO₃ and saturated aqueous NaCl, dried over MgSO₄,filtered and concentrated. Purification by MPLC (50% ethyl acetate inheptane) gave the crude product as an oil which was redissolved in 6NHCl (10 mL) and heated to 70° C. for 16 h. After cooling to roomtemperature, the reaction mixture was transferred to a separatoryfunnel, diluted with deionized water (10 mL) and washed withdichloromethane (5×10 mL). The aqueous layer was concentrated to give anoff-white solid product (68 mg, 42%) as diHCl salt. ¹H NMR (D₂O, 300MHz) δ 8.51 (d, J=1.2 Hz, 1H), 7.25 (d, J=1.2 Hz, 1H), 3.30 (d_(AB),J=15.9 Hz, 1H), 3.18 (d_(AB), J=15.9 Hz, 1H), 1.92-1.78 (m, 1H), 1.70(ddd, J=14.7, 12.0, 4.2 Hz, 1H), 1.32-1.16 (m, 3H), 1.16-0.99 (m, 1H),0.59 (t, J=7.5 Hz, 2H). ESI MS found for C₁₀H₁₈BN₃O₄ m/z [256.2 (M+1)].

Example 103: Preparation of 2-(4-boronobutyl)pyrrolidine-2-carboxylicacid hydrochloride

2-(4-Boronobutyl)pyrrolidine-2-carboxylic acid hydrochloride is preparedin a manner analogous to that set forth in Example 102, exceptdi-tert-butyl pyrrolidine-1,2-dicarboxylate is used as the startingamino acid derivative in step 1. ¹H NMR (D₂O, 300 MHz) δ 3.36-3.24 (m,2H), 2.41-2.33 (m, 1H), 2.08-1.70 (m, 5H), 1.39-1.12 (m, 4H), 0.71 (t,J=7.2 Hz, 2H). ESI MS found for C₉H₁₈BNO₄ m/z [216.0 (M+1)].

Example 104: Preparation of 2-amino-6-borono-2-isobutylhexanoic acidhydrochloride

2-Amino-6-borono-2-isobutylhexanoic acid hydrochloride is prepared in amanner analogous to that set forth in Example 102, except tert-butyl2-(diphenylmethyleneamino)-4-methylpentanoate is used as the startingamino acid derivative in step 1. ¹H NMR (D₂O, 300 MHz) δ 1.80-1.47 (m,5H), 1.29-1.15 (m, 3H), 1.08-0.94 (m, 1H), 0.75 (d, J=6.6 Hz, 3H), 0.70(d, J=6.6 Hz, 3H), 0.58 (t, J=7.8 Hz, 2H). ESI MS found for C₁₀H₂₂BNO₄m/z [232.1 (M+1)].

Example 105: Preparation of 2-amino-6-borono-2-isopropylhexanoic acidhydrochloride

2-Amino-6-borono-2-isobutylhexanoic acid hydrochloride is prepared in amanner analogous to that set forth in Example 102, except tert-butyl2-(diphenylmethyleneamino)-3-methylbutanoate is used as the startingamino acid derivative in step 1. ¹H NMR (D₂O, 300 MHz) δ 2.08 (heptet,J=6.9 Hz, 1H), 1.78-1.70 (m, 2H), 1.31-1.15 (m, 3H), 1.10-0.97 (m, 1H),0.84 (d, J=6.9 Hz, 3H), 0.82 (d, J=6.9 Hz, 3H), 0.61 (t, J=7.5 Hz, 2H).ESI MS found for C₉H₂₀BNO₄ m/z [218.1 (M+1)].

Example 106: Preparation of 2-amino-2-(4-boronobutyl)succinic acidhydrochloride

2-Amino-2-(4-boronobutyl)succinic acid hydrochloride is prepared in amanner analogous to that set forth in Example 102, except di-tert-butyl2-(diphenylmethyleneamino)succinate is used as the starting amino acidderivative in step 1. ¹H NMR (D₂O, 500 MHz) δ 3.10 (d, J=18.0 Hz, 1H),2.85 (d, J=18.0 Hz, 1H [AB system], 1.85-1.78 (m, 2H), 1.37-1.32 (m,3H), 1.23-1.19 (m, 1H), 0.72 (t, J=7.0 Hz, 2H). ESI MS found forC₈H₁₆BNO₆ m/z [216.4, (M+1−18) 100%, 198.3 (M+1−2×18) 35%, 232.4 (M−1)50%, 214.4 (M−1−18) 100%].

Example 107: Preparation of2-amino-6-borono-2-((1-isopropyl-1H-imidazol-5-yl)methyl)hexanoic aciddihydrochloride

A solution of tert-butyl2-(tert-butoxycarbonylamino)-2-(2-oxoethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(prepared in a manner analogous to that described in example 16) 100 mg(0.22 mmol) in methanol (1 mL) was treated with tosmethyl isocyanide (59mg, 0.30 mmol) followed by iso-propyl amine (59 mg, 85 uL, 1.00 mmol) atroom temperature. The reaction mixture was stirred at room temperaturefor 48 hours, then evaporated and purified by chromatography(chloroform:methanol; gradient 100:1 to 10:1) to give 35 mg of thealkylated product (white solid), which was redissolved in 6 N HCl (10mL) and heated to 70° C. for 16 h. After cooling to room temperature,the reaction mixture was transferred to a separatory funnel, dilutedwith deionized water (10 mL) and washed with dichloromethane (5×10 mL).The aqueous layer was concentrated to give2-amino-6-borono-2-((1-isopropyl-1H-imidazol-5-yl)methyl)hexanoic aciddihydrochloride as an off-white solid product (20 mg, 26% yield). ¹H NMR(D₂O, 300 MHz) δ 8.71 (d, J=1.2 Hz, 1H), 7.24 (d, J=1.2 Hz, 1H), 4.45(heptet, J=6.3 Hz, 1H), 3.35 (d_(AB), J=16.2 Hz, 1H), 3.21 (d_(AB),J=16.2 Hz, 1H), 1.98-1.86 (m, 1H), 1.82-1.68 (m, 1H), 1.38-1.20 (m, 3H),1.37 (d, J=6.3 Hz, 3H), 1.32 (d, J=6.3 Hz, 3H), 1.17-1.03 (m, 1H), 0.62(t, J=7.5 Hz, 2H). ESI MS found for C₁₃H₂₄BN₃O₄ m/z [298.2 (M+1)].

Example 108: Preparation of 2-amino-6-borono-2-(1-hydroxypropyl)hexanoicacid hydrochloride Step 1: tert-butyl2-(diphenylmethyleneamino)hex-5-enoate

While under a nitrogen atmosphere a stirred solution of(benzhydrylidene-amino)-acetic acid tert-butyl ester (5 g, 16.9 mmol) inTHF (80 mL, 0.2 M) was carefully treated with sodiumbis(trimethylsilyl)amide (18.6 mL, 1.0 M, 1.1 equiv) at −78° C. Afterstirring for 30 min, 4-bromo-but-1-ene (2.1 mL, 20.3 mmol, 1.2 equiv)was slowly added. The cooling bath was removed and the reaction mixturegradually warmed to room temperature and stirred for overnight. Thesolution was cooled to 0° C. and quenched with water. The resultingsolution was diluted with ethyl acetate and washed successively withwater and saturated aqueous NaCl, dried over MgSO₄, filtered andconcentrated. Purification by MPLC (1-25% ethyl acetate in heptane) gave2-(benzhydrylidene-amino)-hex-5-enoic acid tert-butyl ester as colorlessoil (5.6 g, 15.9 mmol, 94%).

Step 2: tert-butyl4-(but-3-enyl)-5-ethyl-2,2-diphenyloxazolidine-4-carboxylate

While under a nitrogen atmosphere, a stirred solution of2-(benzhydrylidene-amino)-hex-5-enoic acid tert-butyl ester (350 mg, 1mmol) in THF (5 mL, 0.2 M) was cooled to −78° C. and carefully treatedwith sodium bis(trimethylsilyl)amide (2 mL, 1 M, 2 equiv). Afterstirring 30 min, diethyl aluminum chloride (2.4 mL, 1 M, 2.4 equiv) wasadded and the reaction mixture was stirred an additional 30 min.Propionaldehyde (94 μl, 1.25 mmol, 1.25 eq) was added to the solutionand the cooling bath was removed. After stirring overnight the reactionmixture was cooled to 0° C. and quenched with saturated NH₄Cl. Theresulting solution was diluted with ethyl acetate and washedsuccessively with water and saturated potassium sodium tartrate, driedover MgSO₄, filtered and concentrated. Purification by MPLC (1-40% ethylacetate in heptane) gave4-but-3-enyl-5-ethyl-2,2-diphenyl-oxazolidine-4-carboxylic acidtert-butyl ester (349 mg, 0.86 mmol, 86%).

Step 3: tert-butyl5-ethyl-2,2-diphenyl-4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)oxazolidine-4-carboxylate

A solution of 4-but-3-enyl-5-ethyl-2,2-diphenyl-oxazolidine-4-carboxylicacid tert-butyl ester (230 mg, 0.56 mmol) in dichloromethane (2 mL, 0.3M) was added chlorotris (triphenylphosphine)rhodium(I) (60 mg, 0.065mmol, 10 mol %) at room temperature. After stirring for 30 min,4,4,5,5-Tetramethyl-1,3,2-dioxaborolane (200 μl, 1.3 mmol, 2 eq) wasadded to the reaction mixture and stirred overnight. After quenching thereaction with water (3 mL), the resulting solution was diluted withethyl acetate and washed successively with water and saturated aqueousNaCl, dried over MgSO₄, filtered and concentrated. Purification by MPLC(1-40% ethyl acetate in heptane) gave5-Ethyl-2,2-diphenyl-4-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-butyl]-oxazolidine-4-carboxylicacid tert-butyl ester (152 mg, 0.28 mmol, 50%).

Step 4: 2-amino-6-borono-2-(1-hydroxypropyl)hexanoic acid hydrochloride

A solution of5-ethyl-2,2-diphenyl-4-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-butyl]-oxazolidine-4-carboxylicacid tert-butyl ester (152 mg, 0.28 mmol) in 6 N HCl (4 ml) was stirredat 65° C. for 1 day. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (3 ml) and washed with dichloromethane (3×4 mL). The aqueous layerwas frozen in liquid nitrogen and lyophilized to give2-amino-6-borono-2-(1-hydroxy-propyl)-hexanoic acid hydrochloride aswhite foam (20 mg, 0.074 mmol, 27%). ¹H NMR (D₂O, 300 MHz) δ 3.80 (dd,J=11.4, 1.8 Hz, 1H), 1.88-1.50 (m, 2H), 1.48-0.92 (m, 5H), 0.85 (t,J=7.6 Hz, 3H), 0.63 (t, J=7.6 Hz, 2H).

Example 109: Preparation of2-amino-6-borono-2-(hydroxy(piperidin-4-yl)methyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(hydroxy(piperidin-4-yl)methyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 108, except tert-butyl 4-formylpiperidine-1-carboxylate is usedas the aldehyde in step 2. ¹H NMR (D₂O, 300 MHz) δ 3.80 (d, J=2.9 Hz,1H), 3.36-3.20 (m, 2H), 2.94-2.75 (m, 2H), 1.98-1.34 (m, 7H), 1.34-0.97(m, 4H), 0.63 (t, J=7.6 Hz, 2H).

Example 110: Preparation of2-amino-6-borono-2-(hydroxy(piperidin-3-yl)methyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(hydroxy(piperidin-3-yl)methyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 108, except tert-butyl 3-formylpiperidine-1-carboxylate is usedas the aldehyde in step 2. ¹H NMR (D₂O, 300 MHz) δ 4.05-3.70 (m, 1H),3.60-3.40 (m, 1H), 3.00-2.70 (m, 3H), 2.70-1.60 (m, 7H), 1.60-1.15 (m,4H), 0.85 (t, J=7.1 Hz, 2H).

Example 111: Preparation of2-amino-2-(4-boronobutyl)-6,6,6-trifluoro-3-hydroxyhexanoic acidhydrochloride

2-Amino-2-(4-boronobutyl)-6,6,6-trifluoro-3-hydroxyhexanoic acidhydrochloride is prepared in a manner analogous to that set forth inExample 108, except 4,4,4-trifluorobutanal is used as the aldehyde instep 2. ¹H NMR (D₂O, 300 MHz) δ 3.98-3.84 (m, 1H), 2.50-2.12 (m, 2H),2.06-1.66 (m, 4H), 1.47-1.12 (m, 4H), 0.75 (t, J=7.5 Hz, 2H).

Example 112: Preparation of2-amino-6-borono-2-(hydroxy(pyridin-3-yl)methyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(hydroxy(pyridin-3-yl)methyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 108, except nicotinaldehyde is used as the aldehyde in step 2.¹H NMR (D₂O, 300 MHz) δ 8.84 (s, 1H), 8.75 (d, J=5.9 Hz, 1H), 8.61 (d,J=8.2 Hz, 1H), 8.06 (dd, J=8.2, 5.9 Hz, 1H), 5.27 (s, 1H), 2.06-1.86 (m,1H), 1.84-1.67 (m, 1H), 1.54-1.28 (m, 3H), 1.28-1.08 (m, 1H), 0.74 (t,J=7.8 Hz, 2H).

Example 113: Preparation of2-amino-2-(azetidin-3-yl(hydroxy)methyl)-6-boronohexanoic aciddihydrochloride

2-Amino-2-(azetidin-3-yl(hydroxy)methyl)-6-boronohexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 108, except tert-butyl 3-formylazetidine-1-carboxylate is usedas the aldehyde in step 2. ¹H NMR (D₂O, 300 MHz) δ 4.11 (d, J=6.0 Hz,1H), 4.07-3.78 (m, 4H), 3.40-3.10 (m, 1H), 1.85-1.36 (m, 7H), 1.32-0.92(m, 4H), 0.60 (t, J=7.6 Hz, 2H).

Example 114: Preparation of 5-amino-6-oxo-6-phenylhexylboronic acidhydrochloride Step 1: tert-butyl2-benzoyl-2-(diphenylmethyleneamino)hex-5-enoate

A solution of 2-(benzhydrylidene-amino)-hex-5-enoic acid tert-butylester (350 mg, 1 mmol) in THF (5 mL, 0.2 M) was cooled to −78° C. andtreated with sodium bis(trimethylsilyl)amide (2.2 mL, 1.0 M, 2.2 equiv)drop wise over 5 min and stirred for 30 min. After adding benzoylchloride (140 μl, 1.2 mmol, 1.2 eq), the reaction mixture was warmed upto room temperature and stirred for an additional 1.5 h. The solutionwas cooled to 0° C. and quenched with water (5 mL). The resultingsolution was diluted with ethyl acetate and washed successively withwater and saturated aqueous NaCl, dried over MgSO₄, filtered andconcentrated. Purification by MPLC (1-40% ethyl acetate in heptane gave2-(benzhydrylidene-amino)-2-benzoyl-hex-5-enoic acid tert-butyl ester(477 mg, 1 mmol, 100%).

Step 2: tert-butyl2-benzoyl-2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of 2-(benzhydrylidene-amino)-hex-5-enoic acid tert-butylester (530 mg, 1.17 mmol) in dichloromethane (3 mL, 0.4 M) was treatedwith chloro-1,5-cyclooctadiene iridium (I) dimer (24 mg, 0.036 mmol, 3mol %) and 1,2-bis(diphenyl phosphino) ethane (28 mg, 0.07 mmol, 6 mol%) at room temperature. After stirring for 30 min,4,4,5,5-tetramethyl-1,3,2-dioxaborolane (204 μl, 1.4 mmol, 1.2 eq) wasadded to the reaction mixture and stirring was continued overnight. Thesolution was quenched with water (3 mL). The resulting solution wasdiluted with ethyl acetate and washed successively with water andsaturated aqueous NaCl, dried over MgSO₄, filtered and concentrated.Purification by MPLC (1-40% ethyl acetate in heptane) gave2-(benzhydrylidene-amino)-2-benzoyl-6-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-hexanoicacid tert-butyl ester (370 mg, 0.64 mmol, 54%).

Step 3: 5-amino-6-oxo-6-phenylhexylboronic acid hydrochloride

A solution of2-(benzhydrylidene-amino)-2-benzoyl-6-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-hexanoicacid tert-butyl ester (186 mg, 0.32 mmol) in 6 N HCl (6 mL) was stirredat 65° C. for 1 day. After cooling to room temperature, the reactionmixture was transferred to a separatory funnel, diluted with deionizedwater (5 mL) and washed with dichloromethane (3×5 mL). The aqueous layerwas frozen in liquid nitrogen and lyophilized to give2-amino-6-borono-1-phenyl-hexan-1-one (76.5 mg, 88%). ¹H NMR (D₂O, 300MHz) δ 8.04-7.60 (m, 2H), 7.77 (tt, J=7.6, 1.2 Hz, 1H), 7.61 (d, J=7.6Hz, 2H), 5.18 (dd, J=7.5, 4.7 Hz, 1H), 2.15-1.82 (m, 2H), 1.5-1.2 (m,4H), 0.69 (t, J=7.2 Hz, 2H).

Example 115: Preparation of2-amino-6-borono-2-(2-((R)-pyrrolidin-2-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-((R)-pyrrolidin-2-yl)ethyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 87-A below, except(R)-2-(1-(tert-butoxycarbonyl)pyrrolidin-2-yl)acetic acid is used as thecarboxylic acid in step 1. ¹H NMR (D₂O, 500 MHz) δ 3.52-3.48 (m, 1H),3.21-3.11 (m, 2H), 2.35 (dd, J=16.0, 6.0 Hz, 1H), 2.19-2.12 (m, 2H),1.96-1.89 (m, 1H), 1.85-1.79 (m, 2H) 1.70 (dt, J=14.0, 4.0 Hz, 1H),1.60-1.52 (m, 1H), 1.29-1.21 (m, 3H), 1.12-1.05 (m, 1H), 0.62 (t, J=7.0Hz, 2H). ESI MS found for C₁₁H₂₃BN₂O₄ m/z [481.9 (2M+1−2×18) 2%, 281.6(M+Na⁺) 5%, 263.6 (M+Na⁺−18) 4%, 241.5 (M+1−18) 23%, 223.5 (M+1−2×18)100%, 257.5 (M−1) 8%, 239.5 (M−1−18) 100%.].

Example 116: Preparation of 2-amino-6-borono-2-(2-(pyridin-2-yl)ethyl)hexanoic acid dihydrochloride

Step 1: N-methoxy-N-methyl-3-(pyridin-2-yl)propanamide

A solution of 3-pyridin-2-yl-propionic acid (1.0 g, 6.62 mmol), DMAP (10mg), and N,O-dimethylhydroxylamine hydrochloride (679 g, 7.0 mmol) andEDC (1.34 g, 7.0 mmol) in dichloromethane (40 mL) was treated withtriethylamine (2.8 mL, 20.0 mmol). After stirring at room temperatureovernight, the solution was poured into water, extracted with ethylacetate (3×) and the combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated. Purification by column chromatography (silicagel, 30-100% ethyl acetate in heptane) gaveN-methoxy-N-methyl-3-(pyridin-2-yl)propanamide (1.02 g, 78%) as acolorless oil. ESI MS found for C₁₀H₁₄N₂O₂ m/z [195.1 (M+1)].

Step 2: 1-(pyridin-2-yl)hept-6-en-3-one

While under a nitrogen atmosphere, a solution ofN-methoxy-N-methyl-3-(pyridin-2-yl)propanamide (1.00 g, 5.15 mmol), intetrahydrofuran (10 mL) was cooled to 0° C. and treated with4-butenylmagnesiun bromide (0.5 M in THF, 16 mL, 8.0 mmol) in a dropwisemanner. The solution was stirred for 1 hour at 0° C. then allowed towarm to room temperature for 3 h. The resulting solution was poured intosaturated aqueous sodium chloride (100 mL) and extracted with ethylacetate (3×50 mL). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated. Purification by flash column chromatography(silica gel, 0-25% ethyl acetate in heptane) gave1-(pyridin-2-yl)hept-6-en-3-one as a colorless oil (828 mg, 85%). ESI MSfound for C₁₂H₁₅NO m/z [190.1 (M+1)].

Step 3: 2-acetamido-N-tert-butyl-2-(2-(pyridin-2-yl)ethyl)hex-5-enamide

A solution of 1-(pyridin-2-yl)hept-6-en-3-one (825 mg, 4.36 mmol) andammonium acetate (1.01 g, 13.09 mmol) in 2,2,2-trifluoroethanol (3 mL)was treated with tert-butyl isocyanide (730 mg, 0.99 mL, 8.80 mmol).After stirring at room temperature for 6 days, the reaction mixture waspurified by flash column chromatography (crude reaction mixture loadedon the top of the column; silica gel, 0-10% methanol in dichloromethane)to give 2-acetamido-N-tert-butyl-2-(2-(pyridin-2-yl) ethyl)hex-5-enamideas white solid (1.37 g, 95%). ESI MS found for C₁₉H₂₉N₃O₂ m/z [332.2(M+1)].

Step 6:2-acetamido-N-tert-butyl-2-(2-(pyridin-2-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A solution of2-acetamido-N-tert-butyl-2-(2-(pyridin-2-yl)ethyl)hex-5-enamide (810 mg,2.45 mmol) in dichloromethane (4 mL), was treated withchloro-1,5-cyclooctadiene iridium(I) dimer (35 mg, 2 mol %) and1,2-bis(diphenylphosphino)ethane (42 mg, 4 mol %). The solution wasstirred at room temperature for 30 minutes and then4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (0.76 mL, 5.20 mmol) was addeddropwise, and the reaction was then stirred overnight at roomtemperature. The reaction was poured into water and extracted with ethylacetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated. Purification by flash column chromatography(silica gel, 0-10% methanol in dichloromethane) gave2-acetamido-N-tert-butyl-2-(2-(pyridin-2-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamideas a colorless oil (787 mg, 70%). ESI MS found for C₂₅H₄₂BN₃O₄ m/z[460.3 (M+1)].

Step 7: 2-amino-6-borono-2-(2-(pyridin-2-yl)ethyl)hexanoic acid

The hydrolysis of2-acetamido-N-tert-butyl-2-(2-(pyridin-2-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamideto form 2-amino-6-borono-2-(2-(pyridin-2-yl)ethyl)hexanoic acid was donein a manner analogous to that set forth in Example 1, Step 8. ¹H NMR(D₂O, 300 MHz) δ 8.50 (ddd, J₁=6.0 Hz, J₂=1.5 Hz, J₃=0.6 Hz, 1H), 8.37(ddd, J₁=9.6 Hz, J₂=7.8 Hz, J₃=1.8 Hz, 1H), 7.81-7.74 (m, 2H), 3.22-3.08(m, 1H), 3.03-2.91 (m, 1H), 2.33-2.18 (m, 2H), 1.97-1.72 (m, 2H),1.38-1.06 (m, 4H), 0.64 (t, J=7.5 Hz, 2H). ESI MS found for C₁₃H₂₁BN₂O₄m/z [281.2 (M+1)].

Example 117: Preparation of2-amino-6-borono-2-((1-(3,4-dichlorobenzyl)azetidin-3-yl)methyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-((1-(3,4-dichlorobenzyl)azetidin-3-yl)methyl)hexanoicacid dihydrochloride was made from 1-Cbz-3-azetidineacetic acid in amanner analogous to that set forth in Example 139. ¹H NMR (D₂O, 500 MHz)δ 7.55-7.45 (m, 2H), 7.29-7.17 (m, 1H), 4.17 (pseudo-t_(AB), 2H),4.12-4.03 (m, 1H), 3.91-3.80 (m, 1H), 3.14-2.90 (m, 2H), 2.23-2.05 (m,2H), 2.01-1.55 (m, 3H), 1.33-1.16 (m, 3H), 1.09-1.01 (m, 1H), 0.63 (t,J=7.2 Hz, 2H). ESI MS found for C₁₇H₂₅BCl₂N₂O₄ m/z [385.5 (M−18+1)].

Example 118: Preparation of2-amino-6-borono-2-((1-(2,4-dichlorophenethyl)azetidin-3-yl)methyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-((1-(2,4-dichlorophenethyl)azetidin-3-yl)methyl)hexanoicacid dihydrochloride was made from 1-Cbz-3-azetidineacetic acid in amanner analogous to that set forth in Example 116. ¹H NMR (D₂O, 500 MHz)δ 7.55-7.30 (m, 3H), 3.55-3.45 (m, 1H), 3.31-3.20 (m, 1H), 3.18-2.90 (m,4H), 2.77 (t, J=7.6 Hz, 1H), 2.12-2.05 (m, 1H), 2.02-1.61 (m, 5H),1.32-1.17 (m, 3H), 1.13-1.00 (m, 1H), 0.65 (t, J=7.2 Hz, 2H). ESI MSfound for C₁₈H₂₇BCl₂N₂O₄ m/z [397.5 (M−18+1)].

Example 119: Preparation of2-amino-6-borono-2-(2-(3-(3,4-dichlorophenyl)thioureido) ethyl)hexanoicacid hydrochloride

2-Amino-6-borono-2-(2-(3-(3,4-dichlorophenyl)thioureido) ethyl)hexanoicacid hydrochloride is prepared in a manner analogous to that set forthin Example 16, except tert-butyl 2-(diphenylmethyleneamino)acetate isused in step 1 and the following procedure is used for steps 6 and 7: asolution of aldehyde (5.92 mmol) and benzylamine (11.85 mmol) indichloroethane was stirred at room temperature for 1 h, then treatedwith NaBH(OAc)₃ (17.76 mmol). After 16 h, the reaction was quenched with5% solution of NaHCO₃ and extracted with dichloromethane. The organicextracts were washed successively with 1 M HCl, saturated aqueous sodiumchloride, dried over MgSO₄ and concenrated. The crude product waspurified by flash chromathography, dissolved in pyridine and treatedwith 3,4 dichlorophenylisothiocyanate (1.5 equivalents). After stirringovernight at room temperature, the reaction was concentrated, dissolvedin dichloromethane, washed with 1 M HCl, saturated aqueous sodiumchloride, dried over MgSO₄ and concentrated. Purification by flashchromatography gave the urea which was dissolved in ethanol and treatedwith Pd(OH)₂/C and hydrogen using a Parr apparatus. When reaction wascomplete the catalyst was filtered through a pad of celite and thefiltrate was concentrated to dryness. The resulting oil was treated with6 N HCl and heated to 100° C. for 6 h, cooled to room temperature andconcentrated. Purification by HPLC gaveamino-6-borono-2-(2-(3-(3,4-dichlorophenyl)thioureido) ethyl)hexanoicacid hydrochloride. ¹H NMR (D₂O, 500 MHz) δ 7.39 (d, J=8.4 Hz, 1H), 7.32(s, 1H), 7.01 (d, J=8.4 Hz, 1H), 3.67-3.51 (m, 2H), 2.28-2.17 (m, 1H),2.05-1.96 (m, 1H), 1.84-1.68 (m, 2H), 1.35-1.24 (m, 3H), 1.14-1.04 (m,1H), 0.62 (t, J=7.0 Hz, 2H). ESI MS found for C₁₅H₂₂BCl₂N₃O₄S m/z [404.5(M−18+1)].

Example 120: Preparation of2-amino-6-borono-2-(2-isobutyramidoethyl)hexanoic acid hydrochloride

2-amino-6-borono-2-(2-isobutyramidoethyl)hexanoic acid hydrochloride isprepared in a manner analogous to that set forth in Example 119, exceptisobutyryl chloride is used instead of 3,4 dichlorophenylisocyanate. ¹HNMR (D₂O, 500 MHz) δ 3.22-3.15 (m, 2H), 2.32 (hept, J=6.3 Hz, 1H),2.16-08 (m, 1H), 1.91-1.83 (m, 1H), 1.83-1.74 (m, 1H), 1.72-1.64 (m,1H), 1.30-1.22 (m, 3H), 1.12-1.03 (m, 1H), 0.93 (d, J=6.3 Hz, 6H), 0.65(t, J=7.5 Hz, 2H). ESI MS found for C₁₂H₂₅BN₂O₅ m/z [271.5 (M−18+1)].

Example 121: Preparation of2-amino-6-borono-2-(2-(4-(4-chlorophenyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4-(4-chlorophenyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 4-(4-chlorophenyl)piperidine is used as the aminein step 6. ¹H NMR (D₂O, 300 MHz) δ 7.22 (d, J=8.4 Hz, 2H), 7.12 (d,J=8.4 Hz, 2H), 3.60-3.47 (m, 2H), 3.32-3.20 (m, 1H), 3.15-2.95 (m, 3H),2.82-2.70 (m, 1H), 2.31-2.18 (m, 2H), 2.05-1.65 (m, 6H), 1.35-1.15 (m,3H), 1.15-1.01 (m, 1H), 0.63 (t, J=7.2 Hz, 2H). ESI MS found forC₁₉H₃₀BClN₂O₄ m/z [397.3 (M+1)].

Example 122: Preparation of2-amino-6-borono-2-(2-(4-(4-chlorobenzyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4-(4-chlorobenzyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 4-(4-chlorobenzyl)piperidine is used as the aminein step 6. ¹H NMR (D₂O, 500 MHz) δ 7.20 (d, J=8.5 Hz, 2H), 7.05 (d,J=8.5 Hz, 2H), 3.45-3.38 (m, 2H), 3.21-3.15 (m, 1H), 3.04-2.96 (m, 1H),2.82-2.74 (m, 2H), 2.45-2.41 (m, 2H), 2.20-2.14 (m, 2H), 1.85-1.68 (m,5H), 1.35-1.20 (m, 5H), 1.13-1.04 (m, 1H), 0.64 (t, J=7.5 Hz, 2H). ESIMS found for C₂₀H₃₂BClN₂O₄ m/z [375.5 (M−2×18+1)].

Example 123: Preparation of2-amino-2-(azetidin-3-ylmethyl)-6-boronohexanoic acid dihydrochloride

2-amino-2-(azetidin-3-ylmethyl)-6-boronohexanoic acid dihydrochloride isprepared in a manner analogous to that set forth in Example 116, except2-(1-(tert-butoxycarbonyl)azetidin-3-yl)acetic acid is used as thecarboxylic acid in step 1. ¹H NMR (D₂O, 300 MHz) 3.63-3.50 (m, 1H),3.08-2.90 (m, 3H), 2.68-2.43 (m, 2H), 2.12-1.94 (m, 1H), 1.82-1.64 (m,2H), 1.32-1.00 (m, 4H), 0.61 (t, J=7.3 Hz, 2H). ESI MS found forC₁₀H₂₁BN₂O₄ m/z [245.3 (M+1)].

Example 124: Preparation of2-amino-2-(2-(4-benzylpiperidin-1-yl)propyl)-6-boronohexanoic aciddihydrochloride

2-Amino-2-(2-(4-benzylpiperidin-1-yl)propyl)-6-boronohexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 16, except 3-bromo-2-methyl-propene is used as alkyl halide instep 2 and Step 6 is carried out using 4-benzylpiperidine using thefollowing procedure: A mixture of the ketone (235 mg, 0.5 mmol), amine(0.088 ml, 0.5 mmol), and titanium(IV) isopropoxide (0.186 ml, 0.63mmol) was stirred at room temperature under nitrogen. After 1 hr, theviscous solution was diluted with absolute ethanol (0.5 mL). Sodiumcyanoborohydride (21 mg, 0.335 mL) was added, and the solution wasstirred for 1 day. Water was added with stirring, and the resultinginorganic precipitate was filtered and washed with ethanol. The filtratewas then concentrated in vacuo. The crude product was dissolved in ethylacetate, filtered to remove the remaining inorganic solids, andconcentrated in vacuo. The product was then purified by flashchromatography. The aqueous layer was frozen in liquid nitrogen andlyophilized to give the title compound as a colorless foam (97 mg); ¹HNMR (D₂O, 300 MHz) δ 7.28-7.18 (m, 2H), 7.18-7.09 (m, 3H), 3.37-3.08 (m,3H), 3.03-2.70 (m, 2H), 2.51-2.26 (m, 4H), 1.90-1.57 (m, 6H), 1.44-1.02(m, 8H), 0.64 (t, J=7.5 Hz, 2H); MS (+CI): m/z for C₂₁H₃₅BN₂O₄: expected390.32. found 391.2 (M+H)⁺, 373.3 (M+H−H₂O)⁺.

Example 125: Preparation of2-amino-2-(2-(4-benzylpiperidin-1-yl)ethyl)-6-boronohexanoic aciddihydrochloride

2-Amino-2-(2-(4-benzylpiperidin-1-yl)ethyl)-6-boronohexanoic acid isprepared in a manner analogous to that set forth in Example 16, except4-benzylpiperidine is used as the amine in step 6. ¹H NMR (D₂O, 300 MHz)δ 7.28-7.18 (m, 2H), 7.18-7.08 (m, 3H), 3.50-3.36 (m, 2H), 3.24-3.12 (m,1H), 3.08-2.91 (m, 1H), 2.89-2.71 (m, 2H), 2.56-2.43 (m, 2H), 2.23-2.10(m, 2H), 1.89-1.64 (m, 5H), 1.43-1.22 (m, 5H), 1.19-1.04 (m, 1H), 0.66(t, J=7.2 Hz, 2H). ESI MS found for C₂₀H₃₃BN₂O₄ m/z [377.3 (M+1)].

Example 126: Preparation of2-amino-6-borono-2-(2-(4-(4-(trifluoromethyl)benzyl)piperidine-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4-(4-(trifluoromethyl)benzyl)piperidine-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 4-(4-(trifluoromethyl)benzyl)piperidine is used asthe amine in step 6. ¹H NMR (D₂O, 300 MHz) δ 7.53 (d, J=7.8 Hz, 2H),7.27 (d, J=7.8 Hz, 2H), 3.50-3.36 (m, 2H), 3.27-3.12 (m, 1H), 3.07-2.91(m, 1H), 2.90-2.71 (m, 2H), 2.61-2.51 (m, 2H), 2.22-2.09 (m, 2H),1.90-1.62 (m, 5H), 1.45-1.19 (m, 5H), 1.17-1.04 (m, 1H), 0.67 (t, J=7.2Hz, 2H). ESI MS found for C₂₁H₃₂BF₃N₂O₄ m/z [445.3 (M+1)].

Example 127: Preparation of2-amino-6-borono-2-(2-(4-(4-fluorobenzyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4-(4-fluorobenzyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 4-(4-fluorobenzyl)piperidine is used as the aminein step 6. ¹H NMR (D₂O, 500 MHz) δ 7.09 (m, 2H), 6.92 (m, 2H), 3.48-3.39(m, 2H), 3.24-3.12 (m, 1H), 3.06-2.94 (m, 1H), 2.83-2.74 (m, 2H),2.44-2.37 (m, 2H), 2.25-2.17 (m, 2H), 1.88-1.78 (m, 1H), 1.76-1.64 (m,4H), 1.33-1.20 (m, 5H), 1.15-1.02 (m, 1H), 0.64 (t, J=7.2 Hz, 2H). ESIMS found for C₂₁H₃₂BF₃N₂O₄ m/z [395.4 (M+1)].

Example 128: Preparation of2-amino-6-borono-2-(2-(4,4-dimethylpiperidin-1-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(4,4-dimethylpiperidin-1-yl)ethyl)hexanoic acid isprepared in a manner analogous to that set forth in Example 16, except4,4-dimethylpiperidine is used as the amine in step 6. ¹H NMR (D₂O, 500MHz) δ 3.33-3.19 (m, 3H), 3.12-2.94 (m, 3H), 2.29-2.20 (m, 2H),1.90-1.82 (m, 1H), 1.80-1.74 (m, 1H), 1.53-1.48 (m, 4H), 1.33-1.25 (m,3H), 1.16-1.08 (m, 1H), 0.89 (s, 3H), 0.85 (s, 3H), 0.66 (t, J=7.2 Hz,2H). ESI MS found for C₁₅H₃₁BN₂O₄ m/z [315.7 (M+1)].

Example 129: Preparation of2-amino-6-borono-2-(2-(4-propylpiperidin-1-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-(4-propylpiperidin-1-yl)ethyl)hexanoic acid isprepared in a manner analogous to that set forth in Example 16, except4-propylpiperidine is used as the amine in step 6. ¹H NMR (D₂O, 500 MHz)δ 3.49-3.40 (m, 2H), 3.24-3.17 (m, 1H), 3.05-2.97 (m, 1H), 2.88-2.79 (m,2H), 2.24-2.17 (m, 2H), 1.90-1.79 (m, 3H), 1.76-1.70 (m, 1H), 1.53-1.42(m, 1H), 1.35-1.05 (m, 10H), 0.74 (t, J=6.9 Hz, 2H), 0.65 (t, J=7.2 Hz,2H). ESI MS found for C₁₆H₃₃BN₂O₄ m/z [329.7 (M+1)].

Example 130: Preparation of2-amino-6-borono-2-(2-(2-ethyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride

Step 1: Synthesis of (E)-tert-butyl3-(3-ethoxy-3-oxoprop-1-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate

A solution of tert-butyl3-formyl-3,4-dihydroisoquinoline-2(1H)-carboxylate (8.4 g, 32.2 mmol) indry THF (200 mL, 0.16 M) was treated with(ethoxycarbonylmethylene)triphenylphosphorane (12.8 g, 37.0 mmol) in oneportion. After stirring at room temperature overnight, the solvent wasevaporated, and the resulting residue was dissolved in ether. Heptanewas added and the precipitated triphenylphosphine oxide was filteredoff. The filtrate was concentrated and purified by flash chromatography(5-20% ethyl acetate in hexane) affording (E)-tert-butyl3-(3-ethoxy-3-oxoprop-1-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylateas yellow oil (8.7 g, 82%). ¹H NMR (CDCl₃, 500 MHz) δ 7.21-7.14 (m, 2H),7.14-7.07 (m, 2H), 6.74 (dd, J₁=15.8 Hz, J₂=4.8 Hz, 1H), 5.79 (dd,J₁=15.8 Hz, J₂=1.3 Hz, 1H), 4.72 (d, J=16.5 Hz, 1H), 4.35 (d, J=16.5 Hz,1H), 4.11 (qw, J=14.4 Hz, 2H), 3.18 (dd, J₁=15.8 Hz, J₂=6.2 Hz 1H), 2.84(d, J=15.8 Hz, 1H), 1.49 (s, 9H), 1.23 (t, J=14.4 Hz, 3H). ESI MS foundfor C₁₉H₂₅NO₄ m/z [354.4 (M+23)].

Step 2: Synthesis of3-(2-(tert-butoxycarbonyl)-1,2,3,4-tetrahydroisoquinolin-3-yl)propanoicacid

A solution of (E)-tert-butyl3-(3-ethoxy-3-oxoprop-1-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate(8.7 g, 26.3 mmol) and Pd/C (cat) in ethanol (150 mL, 0.18 M) wasevacuated to remove air then treated with hydrogen via a balloon. Afterstirring for 4 h, 3 M sodium hydroxide was added to adjust the solutionto pH 11 and the mixture was stirred overnight. The resulting solutionwas filtered, concentrated, acidified to pH 2 and extracted with ethylacetate. The organic layer was dried over MgSO₄, filtered andconcentrated to give3-(2-(tert-butoxycarbonyl)-1,2,3,4-tetrahydroisoquinolin-3-yl)propanoicacid as a yellow oil (7.7 g, 96%). ESI MS found for C₁₇H₂₃NO₄ m/z [328.4(M+23)]. The crude product was used without further purification.

Step 3: Synthesis of tert-butyl3-(3-(methoxy(methyl)amino)-3-oxopropyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate

A solution of3-(2-(tert-butoxycarbonyl)-1,2,3,4-tetrahydroisoquinolin-3-yl)propanoicacid (7.7 g, 25.2 mmol) in dichloromethane (200 mL, 0.13 M) was treatedwith CDI (6.1 g, 37.8 mmol) in three portions over 10 min with vigorousstirring. After the addition was complete, the mixture was stirred foran additional 40 min and treated with N,O-dimethylhydroxylaminehydrochloride (3.7 g, 37.2 mmol) and stirred overnight. The resultingsolution was washed successively with water, 1 M HCl, 1 M NaOH, sat'd aqsodium chloride, dried over anhydrous MgSO₄, filtered and concentratedto give tert-butyl3-(3-(methoxy(methyl)amino)-3-oxopropyl)-3,4-dihydroisoquinoline-2(1H)-carboxylateas a yellow oil (8.6 g, 98%). LCMS, C₁₉H₂₈N₂O₄ m/z [371.4 (M+23)]. Thecrude product was used without further purification.

Step 4: Synthesis of tert-butyl3-(3-oxohept-6-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate

While under an atmosphere of argon, a flame-dried round-bottomed flaskwas charged with magnesium (1.5 g, 62.9 mmol) a small crystal of I₂ andjust enough dry THF to cover the magnesium. The mixture was heated toreflux until the color dissipated (about 10 min). Approximately 10% of asolution of 4-bromo-1-butene (61.7 mmol) in THF (100 mL) was added allat once. The remainder of the solution was added dropwise whilemaintaining a gentle reflux. After the addition was complete, heatingwas continued for 5 min (until almost all of the Mg had reacted). Thenewly formed Grignard reagent was then added to an ice cooled solutionof tert-butyl3-(3-(methoxy(methyl)amino)-3-oxopropyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate(8.6 g, 24.7 mmol) in dry THF (100 mL). After stirring overnight at roomtemperature, the solution was poured into saturated aqueous ammoniumchloride and extracted with ether (3×). The combined organic extractswere dried over MgSO₄, filtered and concentrated under reduced pressureto give tert-butyl3-(3-oxohept-6-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate (8.0 g,95%). ESI MS found for C₂₁₋₁₂₉NO₃ m/z [366.5 (M+23)]. The crude productwas used without further purification.

Step 5: Synthesis of tert-butyl3-(3-acetamido-3-(tert-butylcarbamoyl)oct-7-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate

A solution of tert-butyl3-(3-oxohept-6-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate (2.0 g,5.8 mmol), t-butyl isonitrile (2.7 mL, 23.3 mmol) and ammonium acetate2.7 g (34.8 mmol) in 2,2,2-trifluoroethanol (3 mL, 1.9 M) was stirred atroom temperature until thin-layer chromatography (TLC) indicated thestarting ketone was consumed. Once complete, the reaction was dilutedwith ethyl acetate, quenched with 2 M HCl and extracted with ethylacetate. The organic layer was washed successively with 2 M HCl andsat'd aq sodium chloride, dried over MgSO₄, filtered and concentrated.Purification by column chromatography (ethyl acetate in hexanes) gavetert-butyl3-(3-acetamido-3-(tert-butylcarbamoyl)oct-7-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylateas yellow oil (1.5 g, 53%). ESI MS found for C₂₈H₄₃N₃O₄ m/z [508.6(M+23)].

Step 6: Synthesis of tert-butyl3-(3-acetamido-3-(tert-butylcarbamoyl)-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)heptyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate

While under an atmosphere of argon, a solution ofbis(1,5-dicyclooctadiene)diiridium(I)dichloride (54 mg, 3% mol),diphenylphosphinoethane (64 mg, 6% mol) and4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.5 mL, 10.7 mmol) in drydichloromethane (20 mL) was cooled to 0° C. A second solution oftert-butyl3-(3-acetamido-3-(tert-butylcarbamoyl)oct-7-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate(1.5 g, 2.67 mmol) in dry dichloromethane (20 mL) was added in oneportion. After 4 h LCMS indicated all the starting olefin was consumedand the reaction was washed successively with water, sat'd aq sodiumchloride, dried over MgSO₄, filtered and concentrated. Purification byflash chromatography (20-35% ethyl acetate in hexanes) gave tert-butyl3-(3-acetamido-3-(tert-butylcarbamoyl)-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)heptyl)-3,4-dihydroisoquinoline-2(1H)-carboxylateas a yellow oil (1.5 g, 93%). ESI MS found for C₃₄H₅₆BN₃O₆ m/z [614.7(M+1), 633.7 (M+23)].

Step 7: Synthesis of2-acetamido-N-tert-butyl-2-(2-(1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A solution of tert-butyl3-(3-acetamido-3-(tert-butylcarbamoyl)-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)heptyl)-3,4-dihydroisoquinoline-2(1H)-carboxylatein ethyl acetate was treated with a solution of HCl (g) in ethyl acetate(approximately 2 M). After stirring for 30 min the reaction wasconcentrated to dryness and the crude hydrochloride product was usedwithout further purification.

Step 8: Synthesis of2-acetamido-N-tert-butyl-2-(2-(2-ethyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A solution of acetaldehyde (0.06 mL, 1.1 mmol) and2-acetamido-N-tert-butyl-2-(2-(1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(0.51 g, 1.0 mmol) in dichloromethane was stirred at room temperaturefor 1 h, then treated with sodium triacetoxyborohydride (0.63 g, 3mmol). After stirring overnight, the reaction was quenched with 5% aqNaHCO₃ (W/V) and extracted with dichloromethane. The organic layer waswashed successively with 1 M HCl, sat'd aq sodium chloride, dried overMgSO₄, filtered and concentrated. Purification by flash chromatography(1% methanol in chloroform) gave2-acetamido-N-tert-butyl-2-(2-(2-ethyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamideas an oil (0.45 g, 83%). ESI MS found for C₃₁H₅₂BN₃O₄ m/z [b.e. 542.7(M+1)].

Step 9: Synthesis of2-amino-6-borono-2-(2-(2-ethyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid

A solution of2-acetamido-N-tert-butyl-2-(2-(2-ethyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(0.108 g, 0.2 mmol) in 6 N HCl was heated to reflux for 16 h, cooled toroom temperature and concentrated to dryness. Purified by preparativeHPLC (20% acetonitrile in water with 0.1% trifluoroacetic acid) gave2-amino-6-borono-2-(2-(2-ethyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid as a white solid (90 mg, 83%). ¹H NMR (D₂O, 500 MHz) δ 7.32-7.10(m, 4H), 4.51-4.38 (m, 1H), 4.29-4.20 (m, 1H), 3.83-3.78 (m, 0.5H),3.70-3.64 (m, 0.5H), 3.33-3.08 (m, 3H), 3.03-2.85 (m, 1H), 2.02-1.62 (m,5.5H), 1.50-1.38 (m, 0.5H), 1.35-1.20 (m, 6H), 1.17-1.05 (m, 1H),0.70-0.60 (m, 2H). ESI MS found for C₁₉H₃₁BN₂O₄ m/z [345.4 (M+1−18),327.4 (M+1−2×18)].

Example 131: Preparation of2-amino-6-borono-2-(2-(1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 130, except steps 7 and 8 were omitted. ¹H NMR (D₂O, 500 MHz)δ 7.29-7.13 (m, 4H), 4.33 (bs, 2H), 3.59-3.50 (m, 1H), 3.18 (dd, J₁=17.6Hz, J₂=5.3 Hz, 1H), 2.87 (dd, J₁=17.6 Hz, J₂=10.6 Hz, 1H), 2.12-1.74 (m,6H), 1.41-1.30 (m, 3H), 1.22-1.13 (m, 1H), 0.69 (t, J=7.2 Hz, 2H). ESIMS found for C₁₇H₂₇BN₂O₄ m/z [335.4 (M+1), 317.4 (M+1−18)].

Example 132: Preparation of2-amino-6-borono-2-(2-(2-(4-chlorobenzyl)-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(2-(4-chlorobenzyl)-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 130, except 4-chlorobenzaldehyde was used as the aldehyde inStep 8. ¹H NMR (D₂O, 500 MHz) δ 7.47-7.06 (m, 8H), 4.45-4.11 (m, 4H),3.83-3.64 (m, 1H), 3.32-3.20 (m, 1H), 3.07-2.90 (m, 1H), 2.05-1.40 (m,6H), 1.39-1.21 (m, 3H), 1.22-1.06 (m, 1H), 0.71-0.60 (m, 2H). ESI MSfound for C₂₄H₃₂BClN₂O₄ m/z [441.4/443.5 (M+1−18)].

Example 133: Preparation of2-amino-6-borono-2-(2-(2-isopentyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(2-isopentyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 130, except isovaleraldehyde was used as the aldehyde in Step8. ¹H NMR (D₂O, 500 MHz) δ 7.34-7.10 (m, 4H), 4.50-4.38 (m, 1H),4.31-4.18 (m, 1H), 3.82-3.75 (m, 0.5H), 3.70-3.62 (m, 0.5H), 3.28-2.85(m, 4H), 2.00-1.41 (m, 9H), 1.35-1.20 (m, 3H), 1.18-1.06 (m, 1H),0.86-0.75 (m, 6H), 0.70-0.60 (m, 2H). ESI MS found for C₂₂H₃₇BN₂O₄ m/z[427.2 (M+23), 387.5 (M+1-18)].

Example 134: Preparation of2-amino-6-borono-2-(2-(2-(cyclohexylmethyl)-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(2-(cyclohexylmethyl)-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 130, except cyclohexanealdehyde was used as the aldehyde inStep 8. ¹H NMR (D₂O, 500 MHz) δ 7.35-7.07 (m, 4H), 4.50-4.10 (m, 2H),3.85-3.64 (m, 1H), 3.30-3.12 (m, 1H), 3.08-2.80 (m, 3H), 2.05-1.42 (m,12H), 1.37-1.05 (m, 7H), 1.05-0.88 (m, 2H), 0.70-0.60 (m, 2H). ESI MSfound for C₂₄H₃₉BN₂O₄ m/z [431.6 (M+1), 413.6 (M+1−18)].

Example 135: Preparation of2-amino-6-borono-2-(2-(2-isobutyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(2-isobutyl-1,2,3,4-tetrahydroisoquinolin-3-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 130, except isobutyraldehyde was used as the aldehyde in Step8. ¹H NMR (D₂O, 500 MHz) δ 7.36-7.05 (m, 4H), 4.52-4.12 (m, 2H),3.83-3.65 (m, 1H), 3.30-3.15 (m, 1H), 3.08-2.81 (m, 3H), 2.15-1.96 (m,3.5H), 1.90-1.70 (m, 3H), 1.53-1.45 (m, 0.5H), 1.35-1.27 (m, 3H),1.18-1.07 (m, 1H), 1.01-0.85 (m, 6H), 0.70-0.60 (m, 2H). ESI MS foundfor C₂₁H₃₅BN₂O₄ m/z [391.5 (M+1), 373.5 (M+1−18)].

Example 136: Preparation of6-borono-2-(3-(3,4-dichlorobenzylamino)propyl)-2-(methylamino)hexanoicacid dihydrochloride

Step 1: Synthesis of tert-butyl4-(methoxy(methyl)amino)-4-oxobutylcarbamate

While under an atmosphere of argon, a room temperature solution of4-(tert-butoxycarbonylamino)butanoic acid (20 g, 0.098 mol) indichloromethane (280 mL, 0.35 M) was treated with CDI (17.6 g, 0.108mol). After 1.5 hr, O,N-dimethylhydroxylamine hydrochloride (10.6 g;0.108 mol) was added, and the resulting solution was stirred overnight.The mixture was added to a separatory funnel, diluted withdichloromethane (220 mL) and washed successively with 2 M HCl (2×), 1 MNaOH and sat'd aq sodium chloride, dried over MgSO₄, filtered andconcentrated to give tert-butyl4-(methoxy(methyl)amino)-4-oxobutylcarbamate (23.8 g, 98%). ESI MS foundfor C₁₁H₂₂N₂O₄ m/z [269.4 (M+Na⁺)].

Step 2: Synthesis of tert-butyl 4-oxooct-7-enylcarbamate

While under an atmosphere of nitrogen, a flame-dried round-bottomedflask was charged with magnesium (3.95 g, 0.162 mol) a small crystal ofI₂ and just enough dry THF to cover the magnesium. The mixture washeated to reflux until the color dissipated (about 10 min.). Next, asolution of 4-bromo-1-butene (16.4 mL, 0.162 mmol) in dry THF (70 mL)was added and heating was continued for 10 min. After cooling to roomtemperature, the newly formed Grignard reagent was then added to aice-cooled solution of tert-butyl4-(methoxy(methyl)amino)-4-oxobutylcarbamate (10 g, 0.041 mol) in dryTHF (100 mL). After stirring overnight at room temperature, the solutionwas poured into saturated aqueous ammonium chloride (70 mL) andextracted with ether (2×). The organic extracts were combined and washedsuccessively with 1.0 M aq HCl and sat'd aq sodium chloride, dried overMgSO₄, filtered and concentrated. Purification by flash columnchromatography (15-30% ethyl acetate in hexanes) gave tert-butyl4-oxooct-7-enylcarbamate as a colorless oil (6.04 g, 62%). ESI MS foundfor C₁₃H₂₃NO₃ m/z [264.3 (M+Na⁺)].

Step 3: Synthesis of tert-butyl4-(tert-butylcarbamoyl)-4-(N-methylacetamido)oct-7-enylcarbamate

A solution of tert-butyl 4-oxooct-7-enylcarbamate (300 mg; 1.24 mmol),methylammonium acetate (680 mg, 7.46 mmol) in 2,2,2-trifluoroethanol (2mL) was treated with tert-butyl isocyanide (0.56 mL, 5.0 mmol) andstirred at room temperature for 5 days. Ethyl acetate (5 mL) and 2 M aqHCl (2 mL) were added and the solution was vigorously stirred for 3additional hrs. The phases were separated and the organic phase waswashed successively with water and sat'd aq sodium chloride, dried overMgSO₄, filtered and concentrated. The crude viscous yellow oil residuewas purified by flash column chromatography (2% methanol indichloromethane) to give tert-butyl4-(tert-butylcarbamoyl)-4-(N-methylacetamido)oct-7-enylcarbamate (130mg, 26%). ¹H NMR (CDCl₃, 500 MHz) δ 5.81-5.73 (m, 1H), 5.40 (s, 1H),5.05-4.96 (m, 2H), 4.62 (bs, 1H), 3.15-3.09 (m, 2H), 3.01 (s, 3H)2.17-2.12 (m, 2H), 2.10 (s, 3H) 2.04-1.94 (m, 2H), 1.77-1.71 (m, 2H),1.43 (s, 9H), 1.38-1.34 (m, 2H), 1.32 (s, 9H). ESI MS found forC₂₁H₃₉N₃O₄ m/z [420.5 (M+Na⁺), 442.4 (M+HCOO⁻), 396.6 (M−1)].

Step 4: Synthesis of tert-butyl4-(tert-butylcarbamoyl)-4-(N-methylacetamido)-8-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)octylcarbamate

While under an atmosphere of argon, a solution ofbis(1,5-dicyclooctadiene)diiridium(I)dichloride (6 mg; 0.009 mmol) anddiphenylphosphinoethane (7 mg, 0.018 mmol) in dichloromethane (1 mL) wascooled to 0° C. and treated with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane(0.174 mL, 1.2 mmol). After stirring for 30 min, a solution oftert-butyl4-(tert-butylcarbamoyl)-4-(N-methylacetamido)oct-7-enylcarbamate (120mg, 0.3 mmol) in dichloromethane (4 mL) was added and the solution wasstirred an additional 16 h. Dichloromethane (10 mL) was added, and thesolution was washed successively with water and sat'd aq sodiumchloride, dried over MgSO₄, filtered and concentrated. Purification bycolumn chromatography (3% methanol in dichloromethane) gave tert-butyl4-(tert-butylcarbamoyl)-4-(N-methylacetamido)-8-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)octylcarbamate(142 mg, 90%). ESI MS found for C₂₇H₅₂BN₃O₆ m/z [548.7 (M+Na⁺), 526.7(M+1), 570.8 (M+HCOO⁻), 524.6 (M−1)].

Step 5: Synthesis of ethyl2-(3-aminopropyl)-2-(N-methylacetamido)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoatehydrochloride

A solution of tert-butyl4-(tert-butylcarbamoyl)-4-(N-methylacetamido)-8-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)octylcarbamate(140 mg, 0.266 mmol) in ethyl acetate (2 mL) was treated with anh HCl (2N in ethyl acetate, 10 mL) and stirred at room temp. After 30 min, thesolution was concentrated to give crude ethyl2-(3-aminopropyl)-2-(N-methylacetamido)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoatehydrochloride as a white solid (130 mg). ESI MS found for C₂₀H₃₉BN₂O₅m/z [399.5 (M+1)]. This material was used without further purification.

Step 6: Synthesis of ethyl2-(3-(3,4-dichlorobenzylamino)propyl)-2-(N-methylacetamido)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoatehydrochloride

A solution of 3,4-dichlorobenzaldehyde (55 mg, 0.31 mmol) and ethyl2-(3-aminopropyl)-2-(N-methylacetamido)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoatehydrochloride (120 mg, 0.26 mmol) in dichloromethane (3 mL) was stirredat room temperature. After 30 min, sodium triacetoxyborohydride (138 mg,0.65 mmol) was added in one portion and stirring was continuatedovernight. Once complete, the solution was diluted with dichloromethane(10 mL), quenched with aq 5% NaHCO₃ (W/V, 5 mL) and stirred vigorouslyfor 30 min. The layers were separated and the organic phase was washedwith water and sat'd aq sodium chloride, dried over MgSO₄, filtered andconcentrated. Purification by flash column chromatography (2-20%methanol in dichloromethane) gave ethyl2-(3-(3,4-dichlorobenzylamino)propyl)-2-(N-methylacetamido)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(78 mg). ESI MS found for C₂₇H₄₃BCl₂N₂O₅ m/z [557.6/559.6 (M+1)].

Step 7: Synthesis of6-borono-2-(3-(3,4-dichlorobenzylamino)propyl)-2-(methylamino)hexanoicacid dihydrochloride

A solution of ethyl2-(3-(3,4-dichlorobenzylamino)propyl)-2-(N-methylacetamido)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(76 mg) in aq 6 M HCl was heated to reflux for 16 h, concentrated todryness and purified by preparative HPLC. The resulting residue wasredissolved in 2 N HCl and evaporated to give6-borono-2-(3-(3,4-dichlorobenzylamino)propyl)-2-(methylamino)hexanoicacid dihydrochloride (19 mg, 12%-3 steps). ¹H NMR (D₂O, 500 MHz) δ 7.55(bs, 1H), 7.51 (d, J=7.5 Hz, 1H), 7.28 (d, J=7.5 Hz, 1H), 4.12 (s, 2H),3.02 (t, J=7.2 Hz, 2H), 2.55 (s, 3H), 1.91-1.68 (m, 5H), 1.60-1.49 (m,1H), 1.38-1.29 (m, 2H), 1.28-1.19 (m, 1H), 1.14-1.04 (m, 1H), 0.70 (t,J=7.2 Hz, 2H). ESI MS found for C₁₇H₂₇BCl₂N₂O₄ m/z [405.4/407.4 (M+1)].

Example 137: Preparation of6-borono-2-(methylamino)-2-(3-(pyrrolidin-1-yl)propyl)hexanoic aciddihydrochloride

Step 1: Preparation of tert-butyl 2-(diphenylmethyleneamino)hex-5-enoate

While under an atmosphere of argon, a solution ofN-(diphenylmethylene)glycine tert-butyl ester (6.30 g, 21.33 mmol) and4-bromo-butene (3.45 g, 25.56 mmol) in freshly distilled THF (50 mL) wascooled to −78° C. and treated with sodium bis(trimethylsilyl)amide (23.4mL, 1.0 M in THF). Once the addition was complete, the reaction waswarmed to room temperature and stirred for 16 h, cooled to 0° C.,diluted with ethyl ether and washed successively with saturated aqueousNaHCO₃ and saturated aqueous NaCl, dried over MgSO₄, filtered andconcentrated. Rapid purification by MPLC (1-25% ethyl acetate in heptaneover 8 CV) gave product tert-butyl2-(diphenylmethyleneamino)hex-5-enoate as a colorless oil (7.00 g, 94%).R_(f) 0.50 (30% ethyl acetate in heptane).

Step 2: preparation of tert-butyl2-(diphenylmethyleneamino)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)hex-5-enoate

While under an atmosphere of argon, a solution of tert-butyl2-(diphenylmethyleneamino)hex-5-enoate (7.00 g, 20.06 mmol) in freshlydistilled (THF 50 mL) was cooled to −78° C. and treated with sodiumbis(trimethylsilyl)amide (60 mL, 1.0 M in THF). After stirring for 10min 2-(4-iodobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (12.4 g,40.0 mmol) was added and the reaction was warmed to room temperature andstirred for 16 h. Next, the reaction mixture was cooled to 0° C.,diluted with ethyl ether and washed successively with saturated aqueousNaHCO₃ and saturated aqueous NaCl, dried over MgSO₄, filtered andconcentrated. Purification by MPLC (1-20% ethyl acetate in heptane with0.5% triethylamine over 6 CV) gave tert-butyl2-(diphenylmethyleneamino)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)hex-5-enoateas a colorless oil (8.50 g, 80%). R_(f) 0.55 (30% ethyl acetate inheptane). ESI MS found for C₃₃H₄₆BNO₄ m/z [532.5 (M+1)].

Step 3: preparation of tert-butyl2-(tert-butoxycarbonylamino)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)hex-5-enoate

A solution of tert-butyl2-(diphenylmethyleneamino)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)hex-5-enoate(5.31 g, 10.0 mmol) in diethyl ether (25 mL) was treated with 1 N HCl(25 mL). After stirring 4 h, sodium bicarbonate (8.4 g, 0.1 mol) anddi-tert-butyl carbonate (2.40 g, 11.0 mmol) were sequentially added.After 16 h, the layers were separated and the aqueous layer wasextracted with ethyl acetate. The combined organic layers were washedwith saturated aqueous NaCl, dried over MgSO₄, filtered andconcentrated. Purification by MPLC (0-20% ethyl acetate in heptane over8 CV) gave tert-butyl2-(tert-butoxycarbonylamino)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)hex-5-enoateas a colorless oil (3.64 g, 78%). R_(f) 0.55 (30% ethyl acetate inheptane); ESI MS found for C₂₅H₄₆BNO₆ m/z [468.3 (M+1)].

Step 5: preparation of tert-butyl2-(tert-butoxycarbonyl(methyl)amino)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)hex-5-enoate

While under an atmosphere of argon, a solution of tert-butyl2-(tert-butoxycarbonylamino)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)hex-5-enoate(1.35 g, 2.89 mmol) in freshly distilled (THF 5 mL) was cooled to 0° C.and treated with sodium bis(trimethylsilyl)amide (6 mL, 1.0 M in THF)under argon. After stirring for 10 min, iodomethane (2.04 g, 14.4 mmol)was added and the reaction was warmed to room temperature and stirredfor 16 h. After being complete by TLC, the reaction mixture was cooledto 0° C., diluted with ethyl ether and washed with saturated aqueousNaCl, dried over MgSO₄, filtered and concentrated. Purification by MPLC(1-20% ethyl acetate in heptane with 0.5% triethylamine over 8 CV) gavetert-butyl2-(tert-butoxycarbonyl(methyl)amino)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)hex-5-enoateas a colorless oil (1.27 g, 91%). R_(f) 0.35 (20% ethyl acetate inheptane). ESI MS found for C₂₆H₄₈BNO₆ m/z [482.3 (M+1)].

Step 6: preparation of tert-butyl2-(tert-butoxycarbonyl(methyl)amino)-2-(3-oxopropyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of tert-butyl2-(tert-butoxycarbonyl(methyl)amino)-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl)hex-5-enoate(1.10 g, 2.29 mmol) in dichloromethane (30 mL) was cooled to −78° C. andtreated with ozone until a pale blue-gray color appeared. After TLCindicated the absence of starting material, the ozone inlet tube wasreplaced with nitrogen and nitrogen was bubbled through the solution for20 min to remove any excess ozone. Triphenylphosphine (1.50 g, 5.72mmol, 2.5 equiv) was added in one portion, the cooling bath was removedand the mixture was stirred for 4 h. The solution was concentrated andpurified by MPLC (0-40% ethyl acetate in heptane) gave tert-butyl2-(tert-butoxycarbonyl(methyl)amino)-2-(3-oxopropyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateas a colorless oil (780 mg, 70%). R_(f) 0.40 (30% ethyl acetate inheptane). ESI MS found for C₂₅H₄₆BNO₇ m/z [484.3 (M+1)].

Step 6: preparation of tert-butyl2-(tert-butoxycarbonyl(methyl)amino)-2-(3-(pyrrolidin-1-yl)propyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of tert-butyl2-(tert-butoxycarbonyl(methyl)amino)-2-(3-oxopropyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(193 mg, 0.40 mmol, 1.0 equiv) and pyrrolidine (43 mg, 0.60 mmol, 1.5equiv) in 1,2-dichloroethane (2 mL) was treated with sodiumtriacetoxyborohydride (168 mg, 0.80 mmol) in one portion. After stirringat room temperature overnight, the reaction mixture was quenched withsaturated aqueous NaHCO₃ (1 mL) and stirred for an additional 5 min. Theresulting mixture was added to a separatory funnel, diluted withsaturated aqueous NaCl (5 mL) and extracted with dichloromethane (2×10mL). The organic layer was dried over MgSO₄, filtered and concentratedunder reduced pressure. Purification by flash column chromatographyeluting with gradient 1-10% methanol in chloroform gave tert-butyl2-(tert-butoxycarbonylmethyl)amino)-2-(3-(pyrrolidin-1-yl)propyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate as an oil (186 mg, 88%). R_(f) 0.35 (10% methanol indichloromethane). ESI MS found for C₂₉H₅₅BN₂O₆ m/z [539.4 (M+1)].

Step 7: preparation of6-borono-2-(methylamino)-2-(3-(pyrrolidin-1-yl)propyl)hexanoic aciddihydrochloride

A solution of tert-butyl2-(tert-butoxycarbonyl(methyl)amino)-2-(3-(pyrrolidin-1-yl)propyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(183 mg, 0.33 mmol) in 6 N hydrochloric acid (5 mL) was stirred at 95°C. overnight. After cooling to room temperature, the reaction mixturewas transferred to a separatory funnel, diluted with deionized water (5mL) and washed with dichloromethane (3×). The aqueous layer was frozenin liquid nitrogen and lyophilized to give6-borono-2-(methylamino)-2-(3-(pyrrolidin-1-yl)propyl)hexanoic aciddihydrochloride, as a colorless foam (81 mg, 80%). ¹H NMR (D₂O, 300 MHz)δ 3.55-3.45 (m, 2H), 3.14-3.05 (m, 2H), 2.98-2.87 (m, 2H), 2.53 (s, 3H),2.03-1.92 (m, 2H), 1.92-1.76 (m, 6H), 1.76-1.64 (m, 1H), 1.62-1.48 (m,1H), 1.36-1.14 (m, 3H), 1.14-0.98 (m, 1H), 0.64 (t, J=7.2 Hz, 2H). ESIMS found for C₁₄H₂₉BN₂O₄ m/z [301.2 (M+1)].

Example 138: Preparation of6-borono-2-(3-(2,3-dihydro-1H-inden-2-ylamino)propyl)-2-(methylamino)hexanoicacid dihydrochloride

6-Borono-2-(3-(2,3-dihydro-1H-inden-2-ylamino)propyl)-2-(methylamino)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 137, except 2,3-dihydro-1H-inden-2-amine was used as theamine in Step 6. ¹H NMR (D₂O, 300 MHz) δ 7.15-7.04 (m, 4H), 3.94-3.82(m, 1H), 3.25-3.16 (m, 2H), 3.11-2.80 (m, 4H), 2.47 (s, 3H), 1.89-1.40(m, 6H), 1.27-1.07 (m, 3H), 1.07-0.92 (m, 1H), 0.58 (t, J=7.5 Hz, 2H).ESI MS found for C₁₉H₃₁BN₂O₄ m/z [363.3 (M+1)].

Example 139: Preparation of6-borono-2-(3-(4-chlorobenzylamino)propyl)-2-(methylamino)hexanoic aciddihydrochloride

6-Borono-2-(3-(4-chlorobenzylamino)propyl)-2-(methylamino)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 137, except 4-chlorobenzylamine was used as the amine in Step 6.¹H NMR (D₂O, 300 MHz) δ 7.32-7.18 (m, 4H), 4.01 (s, 2H), 2.90 (t, J=7.2Hz, 2H), 2.46 (s, 3H), 1.84-1.38 (m, 6H), 1.28-1.04 (m, 3H), 1.04-0.92(m, 1H), 0.56 (t, J=7.5 Hz, 2H). ESI MS found for C₁₇H₂₈BClN₂O₄ m/z[371.2 (M+1)].

Example 140: Preparation of2-amino-6-borono-2-(3-(2,4-dichlorophenethylamino)propyl)hexanoic aciddihydrochloride

Step 1: Synthesis of tert-butyl4-acetamido-4-(tert-butylcarbamoyl)oct-7-enylcarbamate

A solution of tert-butyl 4-oxooct-7-enylcarbamate (Example 159, 2.17 g,8.99 mmol) and ammonium acetate (4.16 g, 53.9 mmol) in2,2,2-trifluoroethanol (7 mL) was treated with tert-butyl isocyanide(4.1 mL, 35.9 mmol) and stirred at room temperature for 3 days. Ethylacetate (15 mL) and 2 M aq HCl (10 mL) were added and the solution wasvigorously stirred for an additional 3 hrs. The phases were separatedand the organic phase was washed successively with water and sat'd aqsodium chloride, dried over MgSO₄, filtered and concentrated. The crudeviscous yellow residue was purified by flash column chromatography(5-50% ethyl acetate in hexanes) to give tert-butyl4-acetamido-4-(tert-butylcarbamoyl)oct-7-enylcarbamate (2.27 g, 66%). ¹HNMR (CDCl₃, 500 MHz) δ 6.97 (s, 1H), 5.79-5.70 (m, 1H), 5.56 (s, 1H),4.99-4.92 (m, 2H), 4.55 (bs, 1H), 3.08-3.06 (m, 2H), 2.78-2.67 (m, 2H),2.03-1.93 (m, 1H), 1.99 (s, 3H), 1.84-1.76 (m, 1H), 1.42 (s, 9H),1.38-1.34 (m, 2H), 1.36 (s, 9H), 1.29-1.24 (m, 2H), ESI MS found forC₂₀H₃₇N₃O₄ m/z [406.5 (M+Na⁺), 384.6 (M+1), 382.5 (M−1)].

Step 2: Synthesis of tert-butyl4-acetamido-4-(tert-butylcarbamoyl)oct-7-enylcarbamate

While under an atmosphere of argon, a solution ofbis(1,5-dicyclooctadiene)diiridium(I)dichloride (26.2 mg; 0.039 mmol)and diphenylphosphinoethane (31 mg, 0.078 mmol) in dichloromethane (3mL) was cooled to 0° C. and treated with4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.76 mL, 5.2 mmol). Afterstirring for 30 min, a solution of tert-butyl4-acetamido-4-(tert-butylcarbamoyl)oct-7-enylcarbamate (500 mg, 1.3mmol) in dichloromethane (15 mL) was added and the solution was stirredan additional 16 h. Dichloromethane (20 mL) was added, and the solutionwas washed successively with water and sat'd aq sodium chloride, driedover MgSO₄, filtered and concentrated. Purification by columnchromatography (3% methanol in dichloromethane) gave tert-butyl4-acetamido-4-(tert-butylcarbamoyl)oct-7-enylcarbamate (530 mg, 80%).ESI MS found for C₂₆H₅₀BN₃O₆ m/z [534.6 (M+Na⁺), 512.6 (M+1), 510.5(M−1)].

Step 3: Synthesis of2-acetamido-2-(3-aminopropyl)-N-tert-butyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A solution of tert-butyl4-acetamido-4-(tert-butylcarbamoyl)oct-7-enylcarbamate (530 mg, 1.04mmol) in ethyl acetate (5 mL) was treated with anh HCl (2 N in ethylacetate, 15 mL) and stirred at room temp. After 30 min, the solution wasconcentrated to give crude2-acetamido-2-(3-aminopropyl)-N-tert-butyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamidehydrochloride as a white solid (459 mg, 99%). ESI MS found forC₂₁H₄₂BN₃O₄ m/z [434.6 (M+Na⁺), 412.6 (M+1), 410.5 (M−1)]. This materialwas used without further purification.

Step 4: Synthesis of2-acetamido-N-tert-butyl-2-(3-(2,4-dichlorophenethylamino)propyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A solution of (2,4-dichlorophenyl)acetaldehyde (0.8 mmol) and2-acetamido-2-(3-aminopropyl)-N-tert-butyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamidehydrochloride (260 mg, 0.58 mmol) in dichloromethane (5 mL) was stirredat room temperature. After 30 min, sodium triacetoxyborohydride (310 mg,1.45 mmol) was added in one portion and stirring was continuedovernight. Once complete, the solution was diluted with dichloromethane(10 mL), quenched with aq 5% NaHCO₃ (W/V, 5 mL) and stirred vigorouslyfor 30 min. The layers were separated and the organic phase was washedwith water and sat'd aq sodium chloride, dried over MgSO₄, filtered andconcentrated. Purification by flash column chromatography (1-20%methanol in dichloromethane) gave2-acetamido-N-tert-butyl-2-(3-(2,4-dichlorophenethylamino)propyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(140 mg, 47%). ESI MS found for C₂₉H₄₈BCl₂N₃O₄ m/z [584.6/586.6 (M+1)].

Step 5: Synthesis of2-amino-6-borono-2-(3-(2,4-dichlorophenethylamino)propyl)hexanoic acid

A solution of2-acetamido-N-tert-butyl-2-(3-(2,4-dichlorophenethylamino)propyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(140 mg) in aq 6 M HCl was heated to reflux for 16 h, concentrated todryness and purified by preparative HPLC. The residue was redissolved in2 N HCl and evaporated to give2-amino-6-borono-2-(3-(2,4-dichlorophenethylamino)propyl)hexanoic aciddihydrochloride (110 mg, 98%). ¹H NMR (D₂O, 500 MHz) δ 7.45 (bs, 1H),7.23 (bs, 2H), 3.19 (t, J=7.5 Hz, 2H), 3.06-2.95 (m, 4H), 1.91-1.71 (m,5H), 1.60-1.49 (m, 1H), 1.34-1.25 (m, 3H), 1.17-1.08 (m, 1H), 0.69 (t,J=7.2 Hz, 2H). ESI MS found for C₁₇H₂₇BCl₂N₂O₄ m/z [387.5/389.4(M+1−18)].

Example 141: Preparation of2-amino-6-borono-2-(3-(3,4-dichlorobenzylamino)propyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(3-(3,4-dichlorobenzylamino)propyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 140, except 3,4-dichlorobenzaldehyde was used as the aldehyde inStep 4. ¹H NMR (D₂O, 500 MHz) δ 7.57-7.48 (m, 2H), 7.30-7.26 (m, 1H),4.11 (s, 2H), 3.00 (t, J=7.5 Hz, 2H), 1.90-1.68 (m, 5H), 1.63-1.51 (m,1H), 1.35-1.25 (m, 3H), 1.17-1.09 (m, 1H), 0.69 (t, J=7.2 Hz, 2H). ESIMS found for C₁₆H₂₅BCl₂N₂O₄ m/z [391.4/393.4 (M+1)].

Example 142: Preparation of2-amino-6-borono-2-(2-(4-(4-chlorobenzyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(2-(4-(4-chlorobenzyl)piperidin-1-yl)ethyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 16, except 4-(4-chlorobenzyl)piperidine was used as thealdehyde in Step 6. ¹H NMR (D₂O, 500 MHz) δ 7.20 (d, J=8.5 Hz, 2H), 7.05(d, J=8.5 Hz, 2H), 3.45-3.38 (m, 2H), 3.21-3.15 (m, 1H), 3.04-2.96 (m,1H), 2.82-2.74 (m, 2H), 2.45-2.41 (m, 2H), 2.20-2.14 (m, 2H), 1.85-1.68(m, 5H), 1.35-1.20 (m, 5H), 1.13-1.04 (m, 1H), 0.64 (t, J=7.5 Hz, 2H).ESI MS found for C₂₀H₃₂BClN₂O₄ m/z [375.5 (M−2×18+1)].

Example 143: Preparation of2-amino-6-borono-2-(2-((S)-pyrrolidin-2-yl)ethyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(2-((S)-pyrrolidin-2-yl)ethyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 130, except 1-(tert-butoxycarbonyl)pyrrolidine-2-carboxylic acidwas used as the carboxylic acid in Step 1. ¹H NMR (D₂O, 300 MHz) δ3.48-3.36 (m, 1H), 3.23-3.10 (m, 2H), 2.19-2.04 (m, 1H), 2.00-1.45 (m,9H), 1.37-1.21 (m, 3H), 1.19-1.03 (m, 1H), 0.64 (t, J=7.5 Hz, 2H). ESIMS found for C₁₂H₂₅BN₂O₄ m/z [273.2 (M+1), 255.2 (M+1−18)].

Example 144: Preparation of6-borono-2-(methylamino)-2-(2-((S)-pyrrolidin-2-yl)ethyl)hexanoic aciddihydrochloride

6-Borono-2-(methylamino)-2-(2-((S)-pyrrolidin-2-yl)ethyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 130, except 1-(tert-butoxycarbonyl)pyrrolidine-2-carboxylic acidwas used as the carboxylic in Step 1 and methylammonium acetate was usedin place of ammonium acetate in step 5. ¹H NMR (D₂O, 300 MHz) δ3.48-3.34 (m, 1H), 3.23-3.10 (m, 2H), 2.52 (bs, 3H), 2.18-2.04 (m, 1H),2.00-1.70 (m, 6H), 1.70-1.40 (m, 3H), 1.37-1.16 (m, 3H), 1.14-0.97 (m,1H), 0.63 (t, J=7.2 Hz, 2H). ESI MS found for C₁₃H₂₇BN₂O₄ m/z [287.3(M+1), 269.3 (M+1−18)].

Example 145: Preparation of 6-borono-2-(4-chlorobenzylamino)hexanoicacid hydrochloride

Step 1: preparation of ethyl2-(4-chlorobenzylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of ethyl2-amino-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate (119mg, 0.42 mmol) in 1,2-dichloroethane (1 mL) was treated with4-chlorobenzaldehyde (89 mg, 0.63 mmol). After stirring for 10 minutes,sodium triacetoxyborohydride (230 mg, 1.05 mmol) was added and stirringwas continued for 18 hours. The reaction was diluted with ethyl acetate,washed with saturated aq sodium bicarbonate and sat'd aq sodiumchloride, dried over MgSO₄, and concentrated. Purification by columnchromatography (4-32% ethyl acetate in heptane afford ethyl2-(4-chlorobenzylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(59 mg, 34%). R_(f) 0.28 (20% ethyl acetate in heptane). ¹H NMR (CDCl₃,300 MHz) δ 7.29-7.25 (m, 4H), 4.21 (q, J=7.7 Hz, 2H), 3.78, 3.58 (ABq,J_(AB)=13.2 Hz, 2H), 3.20 (t, J=7.0 Hz, 1H), 1.80-1.57 (m, 2H),1.42-1.34 (m, 4H), 1.30-1.21 (m, 15H), 0.77 (t, J=7.0 Hz, 2H). ESI MSfound for C₂H₃₃B₁Cl₁N₁O₄ m/z [410.1 (M+1)].

Step 2: preparation of 6-borono-2-(4-chlorobenzylamino)hexanoic acidhydrochloride

A solution of ethyl2-(4-chlorobenzylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(59 mg) in aq 6 M HCl was heated to reflux for 16 h, concentrated todryness and purified by preparative HPLC. The residue was redissolved in2 N HCl and evaporated to give 6-borono-2-(4-chlorobenzylamino)hexanoicacid hydrochloride (36 mg, 83%). ¹H NMR (CD₃OD, 300 MHz) δ 7.56-7.46 (m,4H), 4.23 (s, 2H), 4.09-3.98 (m, 1H), 2.02-1.91 (m, 2H), 1.52-1.37 (m,4H), 0.81 (t, J=7.0 Hz, 2H). ESI MS found for C₁₃H₁₉B₁Cl₁N₁O₄ m/z [300.2(M+1)].

Example 146: Preparation of 6-borono-2-(methylamino)hexanoic acidhydrochloride

Step 1: preparation of ethyl2-(tert-butoxycarbonyl(methyl)amino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

A solution of ethyl2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(104 mg, 0.27 mmol) in THF (2.7 mL) was cooled to 0° C. and treated withmethyl iodide (0.084 mL, 1.35 mmol) and NaHMDS (0.41 mL, 1 M solution inTHF, 0.41 mmol). After stirring for 16 h at room temperature, additionalmethyl iodide (0.042 mL, 0.77 mmol) was added and the mixture was warmedto 35° C. for 6 hours. The reaction was quenched with saturated NH₄Clsolution (2 mL), diluted with ethyl acetate, washed with saturatedaqueous sodium bicarbonate solution, sat'd aq sodium chloride, driedover MgSO₄ and concentrated. Purification by column chromatography(5-40% ethyl acetate in heptane) gave ethyl2-(tert-butoxycarbonyl(methyl)amino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(59 mg, 55%). R_(f) 0.34 (20% ethyl acetate in heptane). ¹H NMR (CDCl₃,300 MHz) δ 4.72-4.68, 4.43-4.38 (m, 1H, rotamers), 4.15 (q, J=7.3 Hz,2H), 2.81, 2.77 (s, 3H, rotamers), 1.87-1.61 (m, 2H), 1.53-1.23 (m,28H), 0.78 (t, J=7.3 Hz, 2H). ESI MS found for C₂₀H₃₈B₁N₁O₆ m/z [400.5(M+1)].

Step 2: preparation of 6-borono-2-(methylamino)hexanoic acid

A solution of ethyl2-(tert-butoxycarbonyl(methyl)amino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate(59 mg) in aq 6 M HCl was heated to reflux for 16 h, concentrated todryness and purified by preparative HPLC. The residue was redissolved in2 N HCl and evaporated to give 6-borono-2-(methylamino)hexanoic acid asa white solid (24 mg, 72%). ¹H NMR (CD₃OD, 300 MHz) δ 3.94 (t, J=5.9Hz), 2.72 (s, 3H), 1.45-1.34 (m, 4H), 0.81 (t, J=7.0 Hz, 2H). ESI MSfound for C₇H₁₆B₁N₁O₄ m/z [190.0 (M+1)].

Example 147: Preparation of2-amino-6-borono-2-(3-(piperidin-1-yl)propyl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(3-(piperidin-1-yl)propyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 137, except step 5 was omitted and piperidine was used as theamine in Step 6. ¹H NMR (CD₃OD, 300 MHz) δ 3.60-3.49 (m, 2H), 3.24-2.93(m, 4H), 1.99-1.79 (m, 10H), 1.45-1.29 (m, 6H), 0.83 (t, J=6.6 Hz, 2H).ESI MS found for C₁₄H₂₉B₁N₂O₄ m/z [301.10 (M+1)].

Example 148: Preparation of6-borono-2-(methylamino)-2-(3-(piperidin-1-yl)propyl)hexanoic aciddihydrochloride

6-Borono-2-(methylamino)-2-(3-(piperidin-1-yl)propyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 137, except piperidine was used as the amine in Step 6. ¹H NMR(D₂O, 300 MHz) δ 3.37 (d, J=13.2 Hz, 2H), 2.98 (t, J=6.6 Hz, 2H), 2.79(t, J=12.5 Hz. 2H), 2.49 (s, 3H), 1.83-1.39 (m, 10H). 1.35-1.01 (m, 6H),0.67 (t, J=7.7 Hz, 2H). ESI MS found for C₁₅H₃₁B₁N₂O₄ m/z [315.4 (M+1)].

Example 149: Preparation of6-borono-2-(methylamino)-2-(2-(piperidin-1-yl)ethyl)hexanoicaciddihydrochloride

6-Borono-2-(methylamino)-2-(2-(piperidin-1-yl)ethyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 137, except allyl iodide was used as the alkylation agent instep 1 and piperidine was used as the amine in Step 6. ¹H NMR (D₂O, 300MHz) δ 3.48 (br t, J=12.1 Hz), 3.22-3.11 (m, 1H), 3.03-2.76 (m, 3H),2.52 (s, 3H), 2.23-2.03 (m, 2H), 1.85-1.51 (m, 8H), 1.40-1.03 (m, 6H),0.67 (t, J=7.7 Hz, 2H). ESI MS found for C₁₄H₂₉B₁N₂O₄ m/z [301.4 (M+1)].

II. Synthesis of Formula II Compounds

In addition to the foregoing methodologies that are generally applicableto all compounds described herein, the present invention also providesmethodologies that are more specific to compounds of Formula II. Thus,in one embodiment, a Formula II compound synthesis is accomplished usingthe Ugi reaction (Doemling, A., Chem. Rev. 2006, 106, 17-89. This methodis illustrated in Scheme A-I. Thus, treating a ketone or an aldehyde(A-3), with an isocyanate such as tert-butyl isocyanate and an aminesource like ammonium acetate gives an amino acid derivative in which thecarboxylic acid is protected as a tert-butylamide and the α-amine groupis protected as an acetamide. By using different isocyanates and aminesas starting materials, therefore, a series of amino acid precursors areobtained in which the amine and carboxylic acid groups are orthogonallyprotected. If optically active products are desired chiral opticallypure isocyanates and/or amine sources can be used. The reactions usingthese reagents may be enantioselective or, at least, providediastereomeric mixtures of products that can be resolved usinganalytical separation techniques known in the chemical art.

The synthesis of key intermediate A-3 shown in Scheme A-1 can beachieved using several methods. One such method utilizes an activatedcarboxylic acid A-1 and methoxymethylamine to form a Weinreb amide A-2.Alternatively, the carboxylic acid is coupled to the amine using avariety of coupling regents such as EDC, DCC or PyBOP, or directly usingthe acid chloride of A-1. The Weinreb amide is then converted to thedesired ketone by reacting it with an appropriate Grignard reagent togive the desired intermediate A-3 which is reacted with an appropriateisocyanate in the presence of an amine such as ammonium acetate to giveA-4.

Reaction of the terminal olefin of A-4 with a borane source such aspinacolborane gives the protected boronic acid derivative (A-5), whichupon deprotection gives the target compound, an α-borono amino acid A-6.

Those skilled in the art of organic synthesis will recognize thatseveral methods exist for the asymmetric synthesis of substituted aminoacids. See, for example, Vogt, H. and Brase, S. Organic & BiomolecularChemistry 2007, 5, 406-430.

In another embodiment, Formula II compounds are synthesized using thegeneral protocol illustrated in Scheme B-I. Thus, reaction of the ketoneintermediate B-1 (prepared using methods outlines in Scheme A-I), with achiral auxiliary such as (R) or (S)—N-tert-butanesulfinamide (B-2) inthe presence of a Lewis acid like Ti(OEt)₄ results in the formation ofthe corresponding tert-butanesulfinyl imine B-3. See Ellman, J. A.;Owens, T. D. and Tang, T. P. Acc. Chem. Res. 2002, 35, 984-995.

The stereoselective introduction of cyanide is achieved by reactingtert-butanesulfinyl imine B-3 with Et₂AlCN. If the correspondingaminonitrile product B-4 is obtained as a mixture of two isomers, thenthe isomeric mixture is resolved using chromatography. Subsequenthydroboration of the terminal double bond using a wide variety of boranereagents, such as pinacol borane in the presence of an iridium catalystgives the corresponding pinacol borane intermediate B-6. Hydrolysis ofintermediate B-6 using a strong acid like 6 N HCl converts the cyanogroup to a carboxylic acid group and deprotects the dioxaborane moietyto give the target compound B-7.

Those having skill in the art will recognize that the starting materialsand reaction conditions may be varied, the sequence of the reactionsaltered, and additional steps can be employed to synthesize compoundsaccording to Formula II, as demonstrated by the following examples. Asstated above, in some cases, protection of certain reactivefunctionalities may be necessary to achieve some of the abovetransformations. In general, the need for such protecting groups as wellas the conditions necessary to attach and remove such groups will beapparent to those skilled in the art of organic synthesis.

The disclosures of all articles and references mentioned in thisapplication, including patents, are incorporated herein by reference.The preparation of compounds of the present invention is illustratedfurther by the following examples, which are not to be construed aslimiting the invention in scope or spirit to the specific procedures andcompounds described in them.

EXEMPLARY FORMULA II COMPOUNDS Example 1-A:2-amino-6-borono-2-(5′Trifluoromethyl-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-yl)-hexanoicacid hydrochloride

2-Amino-6-borono-2-(5′-trifluoromethyl-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-yl)-hexanoicacid was prepared in a manner analogous to Example 116, except5-trifluoromethyl-3,4,5,6-tetrahydro-2H-[1,2]bipyridinyl-4-carboxylicacid was used in step 1. The product was isolated as a white solid. ¹HNMR (D₂O, 300 MHz) δ 8.12, (s, 1H), 7.98 (d, J==9.5 Hz, 1H), 7.28 (dd,J₁=9.5 Hz, J₂=1 Hz, H), 4.15 (m, 2H), 3.20 (m, 2H), 2.22 (m, 1H), 1.99(d, J=12.5 Hz, 1H), 1.72-1.88 (m, 3H), 1.61 (qd, J₁=12.5 Hz, J₂=3.5 Hz,1H), 1.22-1.39 (m, 4H), 1.09 (m, 1H) and 0.65 (t, J=7 Hz, 2H); MS (+CI):m/z for C₁₇H₂₅BF₃N₃O₄: expected 403.2. found 404.2 (M+H)⁺, 386.3(M+H−H₂O)⁺, 367.9 (M+H−2H₂O)⁺.

Example 2-A:2-amino-6-borono-2-[(4-Trifluoromethyl-pyrimidin-2-yl)-piperidin-4-yl)-hexanoicacid hydrochloride

2-Amino-6-borono-2-[(4-trifluoromethyl-pyrimidin-2-yl)-piperidin-4-yl]-hexanoicacid was prepared in a manner analogous to Example 116, except1-(4-trifluoromethyl-pyrimidin-2-yl)-piperidine-4-carboxylic acid wasused in step 1. The product was isolated as its hydrochloride salt as awhite solid. ¹H NMR (D₂O, 300 MHz) δ 8.38, (d, J=5.5 Hz, 1H), 6.97 (d,J=5.5 Hz, 1H), 4.53 (m, 2H), 2.97 (m, 2H), 2.18 (m, 1H), 1.79-1.92 (m,3H), 1.66, (m, 1H), 1.47 (qd, J₁=13 Hz, J₂=4 Hz, 1H), 1.17-1.34 (m, 4H),1.09 (m, 1H) and 0.65 (t, J=7.5 Hz, 2H); MS (+CI): m/z forC₁₆H₂₄BF₃N₄O₄: expected 404.2. found 405.2 (M+H)⁺, 387.2 (M+H−H₂O)⁺,369.1 (M+H−2H₂O)⁺.

Example 3-A:2-amino-6-borono-2-[(2-Trifluoromethyl-quinolin-4-yl)-piperidin-4-yl)-hexanoicacid hydrochloride

2-Amino-6-borono-2-[(2-trifluoromethyl-quinolin-4-yl)-piperidiny-4-yl]-hexanoicacid was prepared in a manner analogous to Example 116, except1-(2-trifluoromethyl-quinolin-4-yl)-piperidine-4-carboxylic acid instep 1. The product was isolated as its hydrochloride salt as a paleyellow solid. ¹H NMR (D₂O, 300 MHz) δ 7.99, (d, J=7.5 Hz, 1H), 7.74-7.85(m, 2H), 7.55 (ddd, J₁=8.5 Hz, J₂=6.5 Hz, J₃=2.5 Hz, 1H), 7.28 (s, 1H),4.35 (m, 2H), 3.46 (m, 2H), 2.29 (m, 1H,), 2.01 (m, 1H), 1.75-1.89 (m,3H), 1.49, (m, 1H), 1.22-1.36 (m, 4H), 1.12 (m, 1H) and 0.67 (t, J=7.5Hz, 2H); MS (+CI): m/z for C₂₁H₂₇BF₃N₃O₄: expected 453.2. found 454.4(M+H)⁺, 436.4 (M+H−H₂O)⁺, 418.0 (M+H−2H₂O)⁺.

Example 4-A:2-amino-6-borono-2-[(6-chlorobenzoxazol-2-yl)-piperidin-4-yl)-hexanoicacid hydrochloride

Step 1: tert-Butyl-4-[methoxy(methyl)carbamoyl]piperidine-1-carboxylate

EDC (6.29 g, 32.8 mmol) was added in several portions to a stirringsolution of piperidine-1,4-dicarboxylic acid, mono tert-butyl ester (5.0g, 21.8 mmol), DMAP (10 mg), and N,O-dimethylhydroxylamine hydrochloride(3.21 g, 32.8 mmol) in dichloromethane (100 mL). To the resultantsolution was added dropwise triethylamine (9.4 mL, 65.6 mmol), and thereaction mixture was stirred at room temperature overnight. The nextday, the reaction mixture was poured into water, and the aqueous layerwas extracted using ethyl acetate (3×). The combined organic phase waswashed with saturated aqueous sodium chloride, dried over anhydrousmagnesium sulfate, filtered and concentrated in vacuo to give acolorless oil. Purification by column chromatography (silica gel, 0-40%ethyl acetate in heptane) gaveten-butyl-4-[methoxy(methyl)-carbamoyl]-piperidine-1-carboxylate (5.04g, 85%) as a colorless oil; ¹H NMR (CDCl₃, 300 MHz) δ 4.16 (m, 2H), 3.70(s, 3H), 3.17 (s, 3H), 2.72-2.86 (m, 3H), 1.62-1.75 (m, 4H) and 1.44 (s,9H).

Step 2: tert-Butyl-4-pent-4-enoyl-piperidine-1-carboxylate

A solution oftert-butyl-4-[methoxy(methyl)-carbamoyl]-piperidine-1-carboxylate (5.04g, 18.53 mmol), in tetrahydrofuran (50 mL) maintained under anatmosphere of nitrogen was cooled to 0° C. To this cold solution wasadded a THF solution of 4-butenylmagnesiun bromide (0.5 M in THF, 45 mL,22.5 mmol) in a dropwise manner. The solution was stirred for 1 hour at0° C. then allowed to warm to room temperature overnight. The resultingsolution was poured into water, acidified to pH 3-4 with 1 Nhydrochloric acid, and extracted with ethyl acetate (3×). The combinedorganic phase was washed with saturated aqueous sodium chloride, driedover anhydrous magnesium sulfate, filtered and concentrated in vacuo.Purification by flash column chromatography (silica gel, 0-25% ethylacetate in heptane) gavetert-butyl-4-pent-4-enoylpiperidine-1-carboxylate as a colorless oil(4.37 g, 88%); ¹H NMR (CDCl₃, 300 MHz) δ 5.79 (m, 1H), 4.98 (m, 2H),4.10 (m, 2H), 2.76 (t, J=11.5 Hz, 2H), 2.54 (m, 2H), 2.46 (tt, J₁=11.5Hz, J₂=3.5 Hz, 1H), 2.32 (m, 2H), 1.78 (m, 2H), 1.48-1.58 (m, 2H) and1.45 (s, 9H).

Step 3: tert-butyl4-(1-acetylamino)-1-tert-butylcarbamoyl-pent-4-enyl)-piperidine-1-carboxylate

A solution of tert-butyl-4-pent-4-enoylpiperidine-1-carboxylate (4.37 g,16.36 mmol) and ammonium acetate (5.11 g, 65.5 mmol) in2,2,2-trifluoroethanol (4 mL) was treated with tert-butyl isocyanide(2.72 g, 3.70 mL, 32.75 mmol). After stirring at room temperature for 8days, the reaction mixture was added to a separatory funnel, dilutedwith water (100 mL) and extracted with ethyl acetate (2×100 mL). Theorganic layer was washed with saturated aqueous sodium chloride, driedover MgSO₄, filtered and concentrated. Purification by flash columnchromatography (silica gel, 10-60% ethyl acetate in heptane) gavetert-butyl4-(lacetylamino)-1-tert-butylcarbamoyl-pent-4-enyl)piperidine-1-carboxylateas white solid (5.4 g, 81%). ¹H NMR (CDCl₃, 300 MHz) δ 6.99 (s, NH, 1H),5.78 (m, 1H), 5.49 (s, NH, 1H), 4.97 (m, 2H), 4.12 (m, 2H), 2.96 (ddd,J₁=16.5 Hz, J₂=11.5 Hz, J₃=5.5 Hz, 1H), 2.62 (m, 2H), 2.35 (tt, J₁=12.5Hz J2=3 Hz, 1H), 2.10-1.96 (m, 1H), 2.00 (s, 3H), 1.64-1.86 (m, 3H),1.48 (m, 1H), 1.43 (s, 9H), 1.36 (s, 9H), 1.20-1.28 (m, 1H), 1.10 (m,1H).

Step 4: 2-acetylamino-2-piperidin-4-yl-hex-5-enoic acid tert-butylamidehydrochloride

4 N hydrogen chloride in dioxane (13.2 ml, 52.7 mmol) was added to astirred dioxane (30 mL) solution of tert-butyl4-(lacetylamino)-1-tert-butylcarbamoyl-pent-4-enyl)piperidine-1-carboxylate(5.4 g, 13.2 mmol). The reaction mixture was stirred for 2 hrs at roomtemperature and then concentrated in vacuo to give the title compound asa white solid, which was used without further purification (4.5 g, 99%).¹H NMR (CDCl₃, 300 MHz) δ 9.51 (br s, 2×NH, 2H), 7.26 (s, NH, 1H), 5.74(m, vinyl CH+NH, 2H), 4.97 (m, 2H), 3.50 (m, 2H), 2.86 (m, 3H), 2.62 (m,1H), 2.05 (s, 3H), 1.62-2.02 (m, 6H), 1.51 (m, 1H), 1.41 (s, 9H),1.21-1.36 (m, 1H).

Step 5:2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)hex-5-enamide

Hunigs base (2.5 mL) was added to a stirred suspension of2-acetylamino-2-piperidin-4-yl-hex-5-enoic acid tert-butylamidehydrochloride (250 mg, 0.73 mmol) and 2,6-dichlorobenzoxazole (172 mg,0.91 mmol) in anhydrous dimethylacetamide (5 mL). The reaction wasstirred at 95° C. overnight under an atmosphere of nitrogen. Afterheating over night, the reaction mixture was cooled to room temperatureand then diluted with diethyl ether. The organic layer was washed withsaturated aqueous sodium chloride (3×), dried over MgSO₄, filtered andconcentrated. The crude product was purified by flash columnchromatography (silica gel, 20-80% ethyl acetate in heptane) to give2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)hex-5-enamideas an off-white solid (240 mg, 72%). ¹H NMR (CDCl₃, 300 MHz) δ 7.24 (d,J=2 Hz, 1H), 7.21 (d, J=8.5 Hz, 1H), 7.12 (dd, J₁=8.5 Hz, J₂=2 Hz, 1H),7.02 (s, NH, 1H), 5.79 (m, 1H), 5.50 (s, NH, 1H), 4.98 (m, 2H), 4.34 (m,2H), 3.00 (m, 3H), 2.49 (tt, J=12.5 Hz, J₂=3 Hz, 1H), 2.10-1.96 (m, 1H),2.03 (s, 3H), 1.74-1.93 (m, 3H), 1.49 (m, 1H), 1.33 (s, 9H), 1.18-1.28(m, 2H).

Step 6:2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A solution of2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)hex-5-enamide(240 mg, 0.52 mmol) in dichloromethane (4 mL), was treated withchloro-1,5-cyclooctadiene iridium(I) dimer (10.4 mg, 3 mol %) and1,2-bis(diphenylphosphino) ethane (12.2 mg, 6 mol %). The solution wasstirred at room temperature for 30 minutes and then4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (0.152 mL, 1.04 mmol) was addeddropwise, and the reaction was stirred overnight at room temperature.The next day, the reaction mixture was poured into water and extractedwith ethyl acetate (3×). The combined organic phase was washed withsaturated aqueous sodium chloride, dried over anhydrous magnesiumsulfate, filtered and concentrated in vacuo. Purification of the crudeproduct by flash column chromatography (silica gel, 30-100% ethylacetate in heptane) gave2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamideas a colorless oil (212 mg, 69%). ¹H NMR (CDCl₃, 300 MHz) δ 7.24 (d, J=2Hz, 1H), 7.20 (d, J=8.5 Hz, 1H), 7.12 (dd, J₁=8.5 Hz, J₂=2 Hz, 1H), 6.97(s, NH, 1H), 5.48 (s, NH, 1H), 4.32 (m, 2H), 3.02 (m, 2H), 2.84 (m, 1H),2.47 (tt, J₁=12.5 Hz, J₂=3 Hz, 1H), 2.01 (s, 3H), 1.86 (m, 2H),1.30-1.55 (m, 6H), 1.34 (s, 9H), 1.24 (s, 12H), 1.02-1.22 (m, 1H), 0.75(t, J=7.5 Hz, 2H).

Step 7:2-amino-6-borono-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)hexanoicacid

A solution of2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(212 mg) in 6 N HCl (15 mL) was stirred at 90° C. for 1 day. Aftercooling to room temperature, the reaction mixture was transferred to aseparatory funnel, diluted with deionized water (10 mL) and washed withdichloromethane (3×). The aqueous solution was concentrated and purifiedby RP-HPLC (10-100% acetonitrile in water) to give the product,2-amino-6-borono-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)hexanoicacid as its dihydrochloride salt and as a white solid (55 mg). ¹H NMR(D₂O, 300 MHz) δ 7.40 (d, J=2 Hz, 1H), 7.24 (dd, J₁=8.5 Hz, J₂=2 Hz,1H), 7.14 (d, J=8.5 Hz, 1H), 4.14 (m, 2H), 3.30 (t, J=13 Hz, 2H), 2.21(m, 1H), 1.98 (m, 1H), 1.80 (m, 3H), 1.64 (m, 1H), 1.38 (m, 1H),1.20-1.32 (m, 3H), 1.06 (m, 1H), 0.61 (t, J=7.5 Hz, 2H); MS (+CI): m/zfor C₁₈H₂₅BClN₃O₅: expected 409.2. found 431.7 (M+Na)⁺, 410.3 (M+H)⁺,392.0 (M+H−H₂O)⁺, 374.4 (M+H−2H₂O)⁺.

Example 5-A:2-amino-6-borono-2-(1-(5-fluoro-3,8-dimethylquinolin-2-yl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(5-fluoro-3,8-dimethylquinolin-2-yl)piperidin-4-yl)hexanoicacid was prepared in a manner analogous to Example 4-A, except2-chloro-5-fluoro-3,8-dimethylquinoline was used as the heteroarylcoupling partner in step 5. The title compound was isolated as itsdihydrochloride salt, as a white solid (54 mg). ¹H NMR (D₂O, 300 MHz) δ8.27 (s, 1H), 7.44 (dd, J₁=9 Hz, J₂=5.5 Hz, 1H), 7.05 (t, J=9 Hz, 1H),4.10 (m, 2H), 3.36 (m, 2H), 2.41 (s, 3H), 2.38 (s, 3H), 2.36-2.51 (m,1H), 2.03 (m, 1H), 1.74-1.93 (m, 4H), 1.49 (m, 1H), 1.20-1.38 (m, 3H),1.11 (m, 1H) and 0.68 (t, J=7 Hz, 2H); MS (+CI): m/z for C₂₂H₃₁BFN₃O₄:expected 431.2. found 432.4 (M+H)⁺, 414.4 (M+H−H₂O)⁺, 396.0 (M+H−2H₂O)⁺.

Example 6-A:2-Amino-6-borono-2-[2-(4-trifluoromethyl-quinolin-2-yl)-piperidin-4-yl]-hexanoicacid dihydrochloride

2-Amino-6-borono-2-[2-(4-trifluoromethyl-quinolin-2-yl)-piperidin-4-yl]-hexanoicacid was prepared in a manner analogous to Example 4-A, except2-chloro-4-trifluoromethyl-quinoline was used as the heteroaryl couplingpartner in step 5. The title compound was isolated as itsdihydrochloride salt, as a white solid (90 mg). ¹H NMR (D₂O, 300 MHz) δ7.90 (d, J=7.5 Hz, 1H), 7.73 (m, 2H), 7.64 (s, 1H), 7.47 (ddd, J₁=8.5Hz, J₂=6.5 Hz J₃=2 Hz, 1H), 4.44 (m, 2H), 3.34 (m, 2H), 2.27 (m, 1H),2.05 (m, 1H), 1.83 (m, 3H), 1.66 (m, 1H), 1.24-1.43 (m, 4H), 1.11 (m,1H) and 0.67 (t, J=7 Hz, 2H); MS (+CI): m/z for C₂₁H₂₇BF₃N₃O₄: expected453.2. found 454.5 (M+H)⁺, 436.5 (M+H−H₂O)⁺, 418.0 (M+H−2H₂O)⁺.

Example 7-A:2-amino-6-borono-2-[2-(6-methyl-4-trifluoromethyl-pyridin-2-yl)-piperidin-4-yl]-hexanoicacid

2-Amino-6-borono-2-[2-(6-methyl-4-trifluoromethyl-pyridin-2-yl)-piperidin-4-yl]-hexanoicacid was prepared in a manner analogous to Example 4-A, except2-chloro-6-methyl-4-trifluoromethyl-pyridine was used as the heteroarylcoupling partner in step 5. The title compound was isolated as itsdihydrochloride salt, as a white solid (118 mg). ¹H NMR (D₂O, 300 MHz) δ7.30 (s, 1H), 6.82 (s, 1H), 4.18 (m, 2H), 3.18 (m, 2H), 2.42 (s, 3H),2.23 (m, 1H), 1.96 (m, 1H), 1.83 (m, 3H), 1.72 (m, 1H), 1.59 (td, J₁=13Hz, J₂=4 Hz, 1H), 1.23-1.38 (m, 3H), 1.10 (m, 1H) and 0.66 (t, J=7.5 Hz,2H); MS (+CI): m/z for C₁₈H₂₇BF₃N₃O₄: expected 417.2. found 418.0(M+H)⁺, 400.1 (M+H−H₂O)⁺, 382.2 (M+H−2H₂O)⁺.

Example 8-A:2-amino-6-borono-2-[2-(6-methyl-4-trifluoromethyl-pyridin-2-yl)-piperidin-4-yl]-hexanoicacid dihydrochloride

2-Amino-6-borono-2-[2-(3,5-dichloro-pyridin-2-yl)-piperidin-4-yl]-hexanoicacid was prepared in a manner analogous to Example 4-A, except2,3,5-trichloro-pyridine was used as the heteroaryl coupling partner instep 5. The title compound was isolated as its dihydrochloride salt, asa white solid (63 mg). ¹H NMR (D₂O, 300 MHz) δ 8.04 (d, J=2.5 Hz, 1H),8.01 (dd, J₁=3 Hz, J₂=2.5 Hz, 1H), 3.85 (m, 2H), 3.04 (m, 2H), 2.14 (m,1H), 1.92 (m, 1H), 1.82 (m, 2H), 1.70 (m, 2H), 1.46 (m, 1H), 1.28 (m,3H), 1.08 (m, 1H) and 0.64 (t, J=7.5 Hz, 2H); MS (+CI): m/z forC₁₆H₂₄BCl₂N₃O₄: expected 403.1. found 404.2 (M+H)⁺, 386.3 (M+H−H₂O)⁺,368.1 (M+H−2H₂O)⁺.

Example 9-A:2-amino-6-borono-2-[2-(4-trifluoromethyl-pyridin-2-yl)-piperidin-4-yl]-hexanoicacid dihydrochloride

2-Amino-6-borono-2-[2-(4-trifluoromethylpyridin-2-yl)-piperidin-4-yl]-hexanoicacid was prepared in a manner analogous to Example 4-A, except2-chloro-4-trifluoromethylpyridine was used as the heteroaryl couplingpartner in step 5. The title compound was isolated as itsdihydrochloride salt, as a white solid (58 mg). ¹H NMR (D₂O, 300 MHz) δ7.87 (d, J=7 Hz, 1H), 7.53, (s, 1H), 6.97 (dd, J₁=7 Hz, J₂=1.5 Hz, 1H),4.17 (m, 2H), 3.22 (m, 2H), 2.21 (m, 1H), 1.98 (m, 1H), 1.72-1.86 (m,3H), 1.59 (m, 1H), 1.25-1.40 (m, 4H), 1.10 (m, 1H) and 0.68 (t, J=7.5Hz, 2H); MS (+CI): m/z for C₁₇H₂₅BF₃N₃O₄: expected 403.2. found 404.4(M+H)⁺, 386.2 (M+H−H₂O)⁺, 368.3 (M+H−2H₂O)⁺.

Example 10-A:2-amino-6-borono-2-(1-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)piperidin-4-yl)hexanoicacid was prepared in a manner analogous to Example 4-A, except2,3-dichloro-5-trifluoromethylpyridine was used as the heteroarylcoupling partner in step 5. The title compound was isolated as itsdihydrochloride salt, as a white solid (93 mg). ¹H NMR (D₂O, 300 MHz) δ8.27 (dd, J₁=2 Hz, J₂=1 Hz, 1H), 8.06, (d, J=2 Hz, 1H), 3.94 (m, 2H),2.87 (m, 2H), 2.09 (m, 1H), 1.78-1.93 (m, 3H), 1.57-1.69 (m, 2H),1.25-1.42 (m, 4H), 1.10 (m, 1H) and 0.66 (t, J=7 Hz, 2H); MS (+CI): m/zfor C₁₇H₂₄BClF₃N₃O₄: expected 437.15. found 438.5 (M+H)⁺, 420.1(M+H−H₂O)⁺, 402.1 (M+H−2H₂O)⁺.

Example 11-A:2-amino-6-borono-2-[(6-chlorobenzothiazol-2-yl)-piperidin-4-yl)-hexanoicacid dihydrochloride

2-Amino-6-borono-2-[(6-chlorobenzothiazol-2-yl)-piperidin-4-yl)-hexanoicacid was prepared in a manner analogous to Example 4-A, except2,6-dichlorobenzothiazole was used as the heteroaryl coupling partner instep 5. The title compound was isolated as its dihydrochloride salt, asa white solid (117 mg). ¹H NMR (D₂O, 300 MHz) δ 7.62 (d, J=2 Hz, 1H),7.35 (dd, J₁=8.5 Hz, J₂=2 Hz, 1H), 7.27 (d, J=8.5 Hz, 1H), 3.96 (m, 2H),3.40 (t, J=13 Hz, 2H), 2.20 (m, 1H), 2.02 (m, 1H), 1.80 (m, 3H), 1.68(m, 1H), 1.42 (m, 1H), 1.24-1.32 (m, 3H), 1.09 (m, 1H), 0.66 (t, J=7.5Hz, 2H); MS (+CI): m/z for C₁₈H₂₅BClN₃O₄S: expected 425.1. found 426.0(M+H)⁺, 408.2 (M+H−H₂O)⁺, 390.1 (M+H−2H₂O)⁺.

Example 12-A:(R)-2-amino-6-borono-2-((S)-1-(4-chlorophenyl)pyrrolidin-3-yl)hexanoicacid hydrochloride

Step 1: 1-(4-chlorophenyl)-pyrrolidine-3-carboxylic acid, methoxy-methylamide

EDC (1.70 g, 8.86 mmol) was added portionwise to a stirred solution of1-(4-chloro-phenyl)-pyrrolidine-3-carboxylic acid (1.0 g, 4.43 mmol),DMAP (5 mg) and N,O-dimethylhydroxylamine hydrochloride (865 mg, 8.86mmol) in dichloromethane (20 mL). To this solution was added dropwisetriethylamine (1.79 g, 2.47 mL, 17.7 mmol) and the reaction mixture wasstirred at room temperature overnight. At the end of stirring, thereaction mixture was poured into water, and extracted with ethyl acetate(3×). The combined organic phase was washed with saturated aqueoussodium chloride, dried over anhydrous magnesium sulfate, filtered andconcentrated in vacuo to give the title compound as a white solid (1.10g. 98%); ¹H NMR (CDCl₃, 300 MHz) δ 7.14 (d, J=8 Hz, 2H), 6.46 (d, J=8Hz, 2H), 3.74 (s, 3H), 3.50-3.56 (m, 2H), 3.40-3.47 (m, 2H), 3.33 (m,1H), 3.23 (s, 3H), 2.20-2.36 (m, 2H).

Step 2: 1-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-pent-4-en-1-one

A solution of 1-(4-chlorophenyl)-pyrrolidine-3-carboxylic acid andmethoxy-methyl amide (1.1 g, 4.1 mmol) in tetrahydrofuran (20 mL) wascooled to 0° C. while maintaining the solution under an atmosphere ofnitrogen. To the cold solution was added a THF solution of4-butenylmagnesium bromide (0.5M in THF, 16.4 mL, 8.2 mmol) in adropwise manner. After stirring for 1 hour the bath was removed andstirring was continued overnight. The resulting solution was poured intowater, acidified to pH 3-4 with 1 N hydrochloric acid and extracted withethyl acetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated. Purification of the crude by flash columnchromatography (silica gel, 0-25% ethyl acetate in heptane) gave thetitle compound as a colorless oil (940 mg, 87%); ¹H NMR (CDCl₃, 300 MHz)δ 7.15 (d, J=9 Hz, 2H), 6.46 (d, J=9 Hz, 2H), 5.81 (m, 1H), 5.12 (m,2H), 3.54 (m, 2H), 3.26-3.39 (m, 3H), 2.62 (m, 2H), 2.36 (m, 2H) and2.12-2.26 (m, 2H).

Step 3:(2S,3′S)-2-Acetylamino-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-hex-5-enoicacid, ten-butylamide

A solution of 1-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-pent-4-en-1-one(940 mg, 3.57 mmol) and ammonium acetate (1.381 g, 17.85 mmol) in2,2,2-trifluoroethanol (2 mL) was treated with tert-butyl isocyanide(594 mg, 810 μL, 7.15 mmol). After stirring at room temperature for 8days, the reaction mixture was added to a separatory funnel, dilutedwith water (20 mL) and extracted with ethyl acetate (2×30 mL). Theorganic layer was washed with saturated aqueous sodium chloride, driedover MgSO₄, filtered and concentrated. Purification of the crude byflash column chromatography (silica gel, 20-70% ethyl acetate inheptane) gave (2S,3′S)-2-acetylamino-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-hex-5-enoicacid, tert-butylamide as a colorless oil (602 mg, 42%) and(2R,3′S)-2-acetylamino-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-hex-5-enoicacid, tert-butylamide as a colorless oil (500 mg, 35%). The ¹H NMRfrequencies for(2S,3′S)-2-acetylamino-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-hex-5-enoicacid, tert-butylamide are as follows: ¹H NMR (CDCl₃, 300 MHz) δ 7.12 (d,J=9 Hz, 2H), 6.98 (s, NH, 1H), 6.44 (d, J=9 Hz, 2H), 5.73-5.86 (m, NH,1H), 5.79 (s, 1H), 5.00 (m, 2H), 3.02-3.38 (m, 6H), 1.80-2.10 (m, 4H),2.01 (s, 3H), 1.55 (m, 1H), 1.37 (s, 9H).

Step 4:(2S,3′S)-2-Acetylamino-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)hexanoic acid, tert-butylamide

A solution of(2S,3′S)-2-Acetylamino-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-hex-5-enoicacid, tert-butylamide (600 mg, 1.48 mmol) in dichloromethane (10 mL),was treated with chloro-1,5-cyclooctadiene iridium(I) dimer (30 mg, 3mol %) and 1,2-bis(diphenylphosphino) ethane (36 mg, 6 mol %). Thesolution was stirred at room temperature for 30 minutes and then4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (0.43 mL, 2.96 mmol) was addeddropwise, and the reaction was then stirred overnight at roomtemperature. The reaction was poured into water and extracted with ethylacetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated in vacuo. Purification of the crude product byflash column chromatography (silica gel, 30-100% ethyl acetate inheptane) gave(2S,3′S)-2-acetylamino-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)hexanoic acid, tert-butylamide as a colorless oil (568 mg, 72%). ¹H NMR(CDCl₃, 300 MHz) δ 7.11 (d, J=8.5 Hz, 2H), 6.93 (s, NH, 1H), 6.43 (d,J=9 Hz, 2H), 5.77 (s, NH, 1H), 3.16-3.38 (m, 4H), 2.94-3.06 (m, 2H),1.92-2.06 (m, 2H), 1.99 (s, 3H), 1.84 (m, 1H), 1.16-1.52 (m, 4H), 1.35(s, 9H), 1.23 (s, 12H) and 0.76 (t, J=7.5 Hz, 2H).

Step 5:(2S,3′S)-2-Amino-6-borono-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-hexanoicacid

A solution of(2S,3′S)-2-Acetylamino-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-hexanoicacid, tert-butylamide (560 mg) in 6 N HCl (15 mL) was stirred at 90° C.for 1 day. After cooling to room temperature, the reaction mixture wastransferred to a separatory funnel, diluted with deionized water (10 mL)and washed with dichloromethane (3×). The aqueous solution wasconcentrated in vacuo. Purification by RP-HPLC (10-100% acetonitrile inwater) gave the desired product,(2S,3′S)-2-Amino-6-borono-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-hexanoicacid as its dihydrochloride salt, as a white solid (92 mg). ¹H NMR (D₂O,300 MHz) δ 7.36 (d, J=8.5 Hz, 2H), 7.12 (d, J=9 Hz, 2H), 3.74 (dd, J₁=11Hz, J₂=9 Hz, 1H), 3.42-3.62 (m, 3H), 3.01 (quint. J=9 Hz, 1H), 2.20 (m,2H), 1.96 (m, 1H), 1.79 (m, 1H), 1.26-1.40 m, (3H), 1.12 (m, 1H), 0.67(t, J=7.5 Hz, 2H); MS (+CI): m/z for C₁₆H₂₄BClN₂O₄: expected 354.15.found 355.1 (M+H)⁺, 319.4 (M+H−2H₂O)⁺.

Example 13-A:(2R,3′S)-2-amino-6-borono-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-hexanoicacid dihydrochloride

(2R,3′S)-2-Amino-6-borono-2-[1-(4-chlorophenyl)-pyrrolidin-3-yl]-hexanoicacid was prepared in a manner analogous to Example 12-A, except thesecond isomer was used from step 3. After RP-HPLC purification (10-100%acetonitrile in water) it was isolated as a white solid (92 mg). ¹H NMR(D₂O, 300 MHz) δ 7.35 (2H, d, J=8.5 Hz, 2H), 7.14 (d, J=8 Hz, 2H), 3.82(dd, J₁=11 Hz, J₂=9.5 Hz, 1H), 3.67 (dd, J₁=11 Hz, J₂=8.5 Hz, 1H), 3.58(dd, J₁=8.5 Hz, J₂=6 Hz, 2H), 2.94 (quint. J=9 Hz, 1H), 2.31 (m, 1H),1.70-1.91 (m, 3H), 1.24-1.36 (m, 3H), 1.12 (m, 1H), 0.63 (t, J=7.5 Hz,2H-); MS (+CI): m/z for C₁₆H₂₄BClN₂O₄: expected 354.15. found 355.1(M+H)⁺, 337.5 (M+H−H₂O)⁺, 319.2 (M+H−2H₂O)⁺.

Example 14-A:2-amino-6-borono-2-[1-(4-chlorophenyl)-5-oxo-pyrrolidin-3-yl]-hexanoicacid hydrochloride

2-Amino-6-borono-2-[1-(4-chlorophenyl)-5-oxo-pyrrolidin-3-yl]-hexanoicacid was prepared in a manner analogous to Example 12-A, except1-(4-chlorophenyl)-5-oxo-pyrrolidine-3-carboxylic acid was used as thecarboxylic acid in step 1. After RP-HPLC purification (10-100%acetonitrile in water), the title compound was isolated as a white solid(19 mg). ¹H NMR (D₂O, 300 MHz) δ 7.29 (d, J=9 Hz, 2H), 7.26 (d, J=9 Hz,2H), 3.84-3.98 (m, 2H), 3.05 (quint. J=8.5 Hz, 1H), 2.74 (dd, J₁=17.5Hz, J₂=9 Hz, 1H), 2.46 (dd, J₁=17.5 Hz, J₂=9 Hz, 1H), 1.70-1.96 (m, 2H),1.24-1.46 (m, 3H), 1.15 (m, 1H), 0.65 (t, J=7.5 Hz, 2H); MS (+CI): m/zfor C₁₆H₂₂BClN₂O₅: expected 368.1. found 369.0 (M+H)⁺, 351.0 (M+H−H₂O)⁺,331.1 (M+H−2H₂O)⁺.

Example 15-A:(R)-2-amino-2-((1S,3R)-3-aminocyclopentyl)-6-boronohexanoic aciddihydrochloride

(R)-2-Amino-2-((1S,3R)-3-aminocyclopentyl)-6-boronohexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 116, except(1S,3R)-3-(tert-butoxycarbonylamino)cyclopentanecarboxylic acid is usedas the acid in step 1. ¹H NMR (D₂O, 300 MHz) δ 3.7-3.5 (m, 1H),2.63-1.38 (m, 9H), 1.38-1.20 (m, 3H), 1.15-1.0 (m, 1H), 0.67 (t, J=7.6Hz, 2H). ESI MS found for C₁₁H₂₃BN₂O₄ m/z [259.4 (M+1)].

Example 16-A:(R)-2-amino-2-((1S,3S)-3-aminocyclopentyl)-6-boronohexanoic aciddihydrochloride

(R)-2-Amino-2-((1S,3S)-3-aminocyclopentyl)-6-boronohexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 116, except(1S,3s)-3-(tert-butoxycarbonylamino)cyclopentanecarboxylic acid is usedas the acid in step 1. ¹H NMR (D₂O, 300 MHz) δ 3.63-3.49 (m, 1H),2.60-1.34 (m, 9H), 1.34-1.14 (m, 3H), 1.13-0.96 (m, 1H), 0.64 (t, J=7.6Hz, 2H). ESI MS found for C₁₁H₂₃BN₂O₄ m/z [241.7 (M+1−H₂O)].

Example 17-A:(S)-2-amino-2-((1R,3S)-3-aminocyclopentyl)-6-boronohexanoic aciddihydrochloride

(S)-2-Amino-2-((1R,3S)-3-aminocyclopentyl)-6-boronohexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 116, except(1R,3S)-3-(tert-butoxycarbonylamino)cyclopentanecarboxylic acid is usedas the acid in step 1. ¹H NMR (D₂O, 300 MHz) δ 3.65-3.47 (m, 1H),2.62-1.36 (m, 9H), 1.34-1.14 (m, 3H), 1.13-0.96 (m, 1H), 0.63 (t, J=7.6Hz, 2H). ESI MS found for C₁₁H₂₃BN₂O₄ m/z [259.1 (M+1)].

Example 18-A: 2-amino-2-(azetidin-3-yl)-6-boronohexanoic aciddihydrochloride

2-Amino-2-(azetidin-3-yl)-6-boronohexanoic acid dihydrochloride isprepared in a manner analogous to that set forth in Example 116, except1-(tert-butoxycarbonyl)azetidine-3-carboxylic acid is used as the acidin step 1. ¹H NMR (D₂O, 300 MHz) δ 4.74-4.57 (m, 1H), 4.45-4.2 (m, 1H),3.47-2.99 (m, 3H), 1.98-1.67 (m, 2H), 1.42-1.20 (m, 4H), 0.73-0.62 (m,2H). ESI MS found for C₉H₁₉BN₂O₄ m/z [253.4 (M+Na)].

Example 19-A: Preparation of 2-amino-6-borono-2-(morpholin-2-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(morpholin-2-yl)hexanoic acid dihydrochloride isprepared in a manner analogous to that set forth in Example 116, except4-(tert-butoxycarbonyl)morpholine-2-carboxylic acid is used as the acidin step 1. ¹H NMR (CD₃OD, 300 MHz) δ 4.26-4.13 (m, 2H), 3.96 (td,J=12.3, 2.7 Hz, 1H), 3.60-3.40 (m, 2H), 3.40-3.28 (m, 1H), 3.17 (td,J=12.6, 4.2 Hz, 1H), 2.02-1.86 (m, 2H), 1.5-1.36 (m, 3H), 1.34-1.18 (m,1H), 0.83 (t, J=7.5 Hz, 2H). ESI MS found for C₁₀H₂₁BN₂O₅ m/z [243.1(M+¹⁻H₂O)].

Example 20-A: Preparation of2-amino-2-(4-aminocyclohexyl)-6-boronohexanoic acid dihydrochloride

2-Amino-2-(4-aminocyclohexyl)-6-boronohexanoic acid dihydrochloride isprepared in a manner analogous to that set forth in Example 116, except4-(tert-butoxycarbonylamino)cyclohexanecarboxylic acid is used as theacid in step 1. ¹H NMR (D₂O, 300 MHz) δ 3.15-2.92 (m, 1H), 2.05-1.42 (m,3H), 1.40-0.92 (m, 7H), 0.62 (t, J=7.4 Hz, 2H). ESI MS found forC₁₂H₂₅BN₂O₄ m/z [273.2 (M+1)].

Example 21-A: Preparation of2-amino-6-borono-2-[cis-4-(4-chloro-benzylamino)-cyclohexyl]hexanoicacid dihydrochloride

Step 1: benzyl cis-4-(methoxy(methyl)carbamoyl)cyclohexylcarbamate

EDC (6.9 g, 36 mmol) was added in several portions to a stirringsolution of cis-4-benzyloxycarbonylamino-cyclohexanecarboxylic acid (5.0g, 18 mmol), DMAP (10 mg), HOBt (10 mg) and N,O-dimethylhydroxylaminehydrochloride (3.5 g, 36 mmol) in dichloromethane (100 mL). To thissolution was added dropwise triethylamine (10 mL, 72.0 mmol), and thereaction mixture was allowed to stir at room temperature overnight.After completion of stirring, the reaction mixture was poured into waterand the aqueous layer was extracted with ethyl acetate (3×). Thecombined organic phase was washed with saturated aqueous sodiumchloride, dried over anhydrous magnesium sulfate, filtered andconcentrated in vacuo to give benzylcis-4-(methoxy(methyl)carbamoyl)cyclohexylcarbamate as a colorless oil(5.48 g, 17.1 mmol, 95%). ¹H NMR (CDCl₃, 300 MHz) δ 7.38-7.28 (m, 5H),5.09 (bs, 2H), 5.02 (m, 1H), 3.92-3.82 (m, 1H), 3.69 (s, 3H), 3.17 (s,3H), 2.81-2.68 (m, 1H), 1.91-1.78 (m, 2H), 1.74-1.6 (m, 6H).

Step 2: benzyl4-chlorobenzyl(cis-4-(methoxy(methyl)carbamoyl)cyclohexyl)carbamate

A solution of benzyl cis-4-(methoxy(methyl)carbamoyl)cyclohexylcarbamatein DMF (12 mL) under an atmosphere of nitrogen was cooled to 0° C.,followed by treatment with sodium hydride (150 mg of 60 wt % NaH in oil,3.75 mmol). After stirring at room temperature for 30 min, the reactionmixture was cooled to 0° C. and charged with 4-chlorobenzyl bromide (793g, 3.75 mmol). The resulting solution was warmed slowly to roomtemperature and stirred for another 16 hr prior to partitioning of thesolution between saturated aqueous NaHCO₃ and ethyl acetate. The aqueouslayer was further extracted with additional ethyl acetate. Afterseparating the organic layer, the combined organic layer was washed withsaturated aqueous sodium chloride, dried using MgSO₄, filtered, andconcentrated to give benzyl4-chlorobenzyl(cis-4-(methoxy(methyl)carbamoyl)cyclohexyl)carbamate as acolorless oil (1.19 g, 2.67 mmol, 86.0%). ¹H NMR (CDCl₃, 300 MHz) δ7.45-7.05 (m, 9H), 5.09 (bs, 2H), 4.41 (bs, 2H), 4.30-4.04 (m, 1H), 3.65(s, 3H), 3.14 (s, 3H), 2.91 (m, 1H), 2.02-1.84 (m, 4H), 1.70-1.47 (m,4H).

Step 3: 1-benzyl 4-chlorobenzyl(cis-4-pent-4-enoylcyclohexyl)carbamate

A solution of benzyl4-chlorobenzyl(cis-4-(methoxy(methyl)carbamoyl)cyclohexyl) carbamate(1.19 g, 2.69 mmol), in tetrahydrofuran (15 mL), maintained under aninert atmosphere of nitrogen was cooled to 0° C. prior to reaction with4-butenylmagnesiun bromide (0.5 M in THF, 13.4 mL, 6.7 mmol) which wasadded as a THF solution dropwise. After stirring for 1 hour at 0° C. thereaction mixture was warmed to room temperature overnight, poured intowater, acidified to pH 3-4 with 1 N hydrochloric acid and extracted withethyl acetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated in vacuo. Purification by flash columnchromatography gave 1-benzyl4-chlorobenzyl(cis-4-pent-4-enoylcyclohexyl)carbamate as a colorless oil(0.98 g, 2.22 mmol, 83%). ¹H NMR (CDCl₃, 300 MHz) δ 7.44-7.02 (m, 9H),5.84-5.68 (m, 1H), 5.13 (bs, 2H), 5.05-4.92 (m, 2H), 4.34 (bs, 2H),4.20-4.00 (m, 1H), 2.58 (m, 3H), 2.33-2.), 2.24 (m, 2H 19-2.07 (m, 2H),1.7-1.4 (m, 6H).

Step 4: benzyl(1R,4s)-4-((S)-2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)cyclohexyl(4-chlorobenzyl)carbamate

Tert-Butyl isocyanide (0.627 mL, 5.55 mmol) was added to a stirredslurry of 1-benzyl 4-chlorobenzyl(cis-4-pent-4-enoylcyclohexyl)carbamate(978 mg, 2.22 mmol) and ammonium acetate (856 mg, 11.1 mmol) in2,2,2-trifluoroethanol (2 mL). After stirring at room temperature for 8days, the reaction mixture was poured into water and extracted withethyl acetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated in vacuo. Purification of the crude reactionby flash column chromatography gave benzyl(1R,4s)-4-((S)-2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)cyclohexyl(4-chlorobenzyl)carbamateas a colorless oil (850 mg, 1.5 mmol, 68%); ¹H NMR (CDCl₃, 300 MHz) δ7.39-6.9 (m, 9H), 5.84-5.68 (m, 1H), 5.54 (bs, 1H), 5.24-5.04 (m, 2H),5.02-4.91 (m, 2H), 4.44-4.28 (bs, 2H), 4.1-3.9 (m, 1H), 2.97-2.82 (m,1H), 2.23-1.93 (m, 5H), 1.90-1.65 (m, 5H), 1.51-0.96 (m, 14H).

Step 5: benzyl(1R,4s)-4-((S)-2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)cyclohexyl(4-chlorobenzyl)carbamate

A solution of benzyl(1R,4s)-4-((S)-2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)cyclohexyl(4-chlorobenzyl)carbamate(850 mg, 1.5 mmol) in dichloromethane (4 mL) was treated withchloro-1,5-cyclooctadiene iridium(I) dimer (30 mg, 3 mol %) and1,2-bis(diphenylphosphino)ethane (36 mg, 6 mol %). After stirring for 30minutes, 4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (0.44 mL, 3 mmol) wasadded dropwise and the stirring was continued overnight. The reactionwas poured into water and extracted with ethyl acetate (3×). Thecombined organic phase was washed with saturated aqueous sodiumchloride, dried over anhydrous magnesium sulfate, filtered andconcentrated in vacuo. Purification by flash column chromatography gavebenzyl(1R,4s)-4-((S)-2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)cyclohexyl(4-chlorobenzyl)carbamateas a colorless oil (770 mg, 1.10 mmol, 74%); ¹H NMR (CDCl₃, 300 MHz) δ7.4-6.85 (m, 9H), 5.43 (br s, 1H), 5.25-5.0 (m, 2H), 4.44-4.28 (m, 2H),4.08-3.72 (m, 2H), 2.80-2.64 (m, 1H), 2.22-2.04 (m, 1H), 1.98-1.90 (m,4H), 1.90-1.62 (m, 4H), 1.46-0.93 (m, 29H), 0.725 (t, J=7.6 Hz, 2H).

Step 6:(S)-2-acetamido-N-tert-butyl-2-((1s,4R)-4-(4-chlorobenzylamino)cyclohexyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A methanolic solution of benzyl(1R,4s)-4-((S)-2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)cyclohexyl(4-chlorobenzyl)carbamate(770 mg, 1.1 mmol, 10 mL methanol), was degassed using argon in a 100 mLround bottom flask which had been saturated with an atmosphere of argon.To this solution was added palladium (25 mg, 10 wt % on active carbon,wet, Degussa type E101 NE/W). After bubbling argon through this solutionfor 10 minutes, argon gas was replaced with a slow stream of hydrogen.After 1.5 h the reaction was complete and solution was purged withargon, filtered through the Celite 545 and the filter cake washed withmethanol. The methanol solution was concentrated to give and collectedsolvents evaporated to give crude(S)-2-acetamido-N-tert-butyl-2-((1s,4R)-4-(4-chlorobenzylamino)cyclohexyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(660 m g 100%) which was used without further purification.

Step 7:(S)-2-amino-6-borono-2-((1s,4R)-4-(4-chlorobenzylamino)cyclohexyl)hexanoicacid dihydrochloride

A solution of(S)-2-acetamido-N-tert-butyl-2((1s,4R)-4-(4-chlorobenzylamino)cyclohexyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(195 mg) in 6 N HCl (6 mL) was stirred at 95° C. for 24 hours. Aftercooling to room temperature, the reaction mixture was transferred to aseparatory funnel, diluted with deionized water (10 mL) and washed withdichloromethane (3×). The aqueous layer was frozen in liquid nitrogenand lyophilized to give(S)-2-amino-6-borono-2-((1s,4R)-4-(4-chlorobenzylamino)cyclohexyl)hexanoicacid dihydrochloride (105 mg), ¹H NMR (D₂O, 300 MHz) δ 7.40-7.24 (m, 4),4.10 (s, 2H), 3.50-2.94 (m, 1H), 2.22-2.06 (m, 2H), 1.98-1.84 (m, 1H),1.78-1.52 (m, 4H), 1.44-1.10 (m, 6H), 1.10-0.88 (m, 2H), 0.63 (t, J=7.6Hz, 2H); MS (+CI): m/z for C₁₉H₃₀BClN₂O₄. found 379.6 (M+1−H₂O)⁺.

Example 22-A: Preparation of(S)-2-amino-6-borono-2-((1r,4S)-4-(4-chlorobenzylamino)cyclohexyl)hexanoicacid dihydrochloride

(S)-2-Amino-6-borono-2-((1r,4S)-4-(4-chlorobenzylamino)cyclohexyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 21-A, excepttrans-4-tert-butoxycarbonylamino-cyclohexanecarboxylic acid is used asthe acid in step 1. ¹H NMR (D₂O, 300 MHz) δ 7.33 (d, J=7.8 Hz, 2H), 7.27(d, J=8.4 Hz, 2H), 4.09 (s, 2H), 3.08-2.96 (m, 1H), 2.20-2.07 (m, 2H),1.98-1.85 (m, 1H), 1.78-1.56 (m, 4H), 1.43-1.10 (m, 6H), 1.10-0.90 (m,2H), 0.63 (t, J=7.6 Hz, 2H); MS (+CI): m/z for C₁₉H₃₀BClN₂O₄. found397.4 (M+1)⁺.

Example 23-A: Preparation of2-amino-6-borono-2-(1-cyclohexylpiperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-cyclohexylpiperidin-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 118, except cyclohexanone is used in place of benzaldehyde instep 6 with a reaction time of 18 h. ¹H NMR (MeOH-d₆, 400 MHz) δ 3.61(m, 2H), 3.16 (m, 3H), 2.32-2.05 (m, 5H), 1.97 (m, 5H), 1.78 (m, 2H),1.55-1.35 (m, 7H), 1.33 (m, 2H), 0.86 (bt, J=7.2 Hz, 2H). ESI⁺ MS foundfor C₁₇H₃₃BN₂O₄ m/z 323.4 (M−18+H); ESI⁻ MS m/z 339.5 (M−H), 321.4(M−18−H).

Example 24-A: Preparation of2-amino-6-borono-2-(1-cyclopentylpiperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-cyclopentylpiperidin-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 118, except cyclopentanone is used in place of benzaldehyde instep 6 with a reaction time of >18 h. ¹H NMR (D₂O, 400 MHz) δ 3.61 (m,2H), 3.39 (m, 1H), 2.90 (m, 2H), 2.04 (m, 3H), 1.88-1.20 (m, 15H), 1.10(m, 1H), 0.69 (bt, J=7.6 Hz, 2H). ESI⁺ MS found for C₁₆H₃₁BN₂O₄ m/z309.4 (M−18+H); ESI⁻ MS m/z 325.4 (M−H), 307.4 (M−18−H).

Example 25-A: Preparation of2-amino-6-borono-2-[1-(4,4-dimethylcyclohexyl)piperidin-4-yl]hexanoicacid dihydrochloride

2-Amino-6-borono-2-[1-(4,4-dimethylcyclohexyl)piperidin-4-yl]hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 118, except 4,4-dimethylcyclohexanone is used in place ofbenzaldehyde in step 6 with a reaction time of 24 h. ¹H NMR (D₂O, 400MHz) δ 3.53 (m, 2H), 3.00 (m, 3H), 2.10 (m, 2H), 1.90-1.70 (m, 6H),1.65-1.40 (m, 5H), 1.35-1.05 (m, 6H), 0.80 (s, 6H), 0.69 (bt, J=7.6 Hz,2H). ESI⁺ MS found for C₁₉H₃₇BN₂O₄ m/z 351.5 (M−18+H); ESI⁻ MS m/z 367.5(M−H), 349.5 (M−18−H).

Example 26-A: Preparation of2-amino-6-borono-2-[1-(4-chlorobenzoyl)piperidin-4-yl]hexanoic acidhydrochloride

Step 1: 2-Amino-6-borono-2-(piperidin-4-yl)hexanoic acid dihydrochloride

A solution of benzyl4-[1-(tert-butylamino)-1-oxo-2-acetamido-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl]piperidine-1-carboxylate(Example 118, Step 4, 9.00 g, 15.7 mmol) in 6 N HCl (157 mL) was heatedat reflux for 18 h. After cooling to room temperature, the reactionmixture was washed with dichloromethane (2×50 mL). The aqueous layer wasconcentrated under reduced pressure, and the gummy residue wasazeotroped twice from toluene and dried under high vacuum to give2-amino-6-borono-2-(piperidin-4-yl)hexanoic acid dihydrochloride (6.84g, >99% yield, contaminated with approx. 1 equivalent of tert-butylaminehydrochloride formed in the reaction) as an off-white foam which wasused without further purification. ESI⁺ MS found for C₁₁H₂₃BN₂O₄ m/z241.3 (M−18+H); ESI⁻ MS m/z 357.3 (M−H), 239.3 (M−18−H).

Step 2: 2-Amino-6-borono-2-[1-(4-chlorobenzoyl)piperidin-4-yl]hexanoicacid hydrochloride

To a stirring solution of crude2-amino-6-borono-2-(piperidin-4-yl)hexanoic acid dihydrochloride (150mg, 0.371 mmol) in dry DMF (7.4 mL) under nitrogen was addedtriethylamine (0.31 mL, 2.23 mmol) to give a white slurry.4-Chlorobenzoyl chloride (0.106 mL, 0.835 mmol) was added dropwise tothe slurry, and the reaction mixture was stirred at room temperatureovernight. The mixture was diluted with water (15 mL) and extracted withethyl acetate (2×20 mL), and the organic phase was back-extracted with 1N HCl (15 mL). The organic layer was discarded, and all aqueous layerswere combined and washed with ethyl acetate (2×15 mL). The aqueous layerwas concentrated under reduced pressure to give the crude product whichwas purified by reverse phase HPLC [Phenomenex Luna 250×30.00 mm, 10micron column. 40 mL/min flow rate. Gradient: solvent A is 0.07% TFA inacetonitrile; solvent B is 0.10% TFA in water; 5% to 50% A over 24 min,then 50% to 100% A over 1 min]. Product fractions were pooled andconcentrated, and the residue was taken up in 0.5 N HCl (3mL)/acetonitrile (6 mL) and concentrated. The residue was once againtreated with 0.5 N HCl (3 mL)/acetonitrile (6 mL) and concentrated anddried under high vacuum overnight to give2-amino-6-borono-2-[1-(4-chlorobenzoyl)piperidin-4-yl]hexanoic acidhydrochloride (75 mg, 47%) as a faint yellow solid. ¹H NMR (MeOH-d₆, 400MHz) δ 7.51 (d, J=8.4 Hz, 2H), 7.42 (d, J=8.4 Hz, 2H), 4.77 (m, 1H),3.82 (m, 1H), 3.19 (m, 1H), 2.85 (m, 1H), 2.25 (m, 1H), 2.10-1.40 (m,8H), 1.28 (m, 2H), 0.85 (bt, J=7.2 Hz, 2H). ESI⁺ MS found forC₁₈H₂₆BClN₂O₅ m/z 379.3 (M−18+H); ESI⁻ MS m/z 395.4 (M−H), 377.4(M−18−H).

Example 27-A: Preparation of2-amino-6-borono-2-[1-acetylpiperidin-4-yl]hexanoic acid hydrochloride

To a stirring solution of crude2-amino-6-borono-2-(piperidin-4-yl)hexanoic acid dihydrochloride(Example 26-A, Step 1, 250 mg, 0.618 mmol) in dry DMF (13 mL) undernitrogen was added triethylamine (0.69 mL, 4.95 mmol) to give a whiteslurry. The resultant slurry was treated with acetic anhydride (0.131mL, 1.39 mmol), added dropwise, and the reaction mixture was stirred atroom temperature for 2.5 h. The mixture was then diluted with ice water(10 mL) and 3 N HCl (5 mL) prior to extraction with ethyl acetate (2×25mL). The aqueous layer was concentrated under reduced pressure to givethe crude product which was purified by reverse phase HPLC [PhenomenexLuna 250×30.00 mm, 10 micron column. 40 mL/min flow rate. Gradient:solvent A is 0.07% TFA in acetonitrile; solvent B is 0.10% TFA in water;2% A for 2 min, 2% to 20% A over 23 min, then 20% to 100% A over 1 min.]Product fractions were pooled and concentrated, and the residue wastaken up in 0.25 N HCl (3 mL)/acetonitrile (8 mL) and concentrated. Theresidue was once again treated with 0.25 N HCl (3 mL)/acetonitrile (8mL) and concentrated and dried under high vacuum overnight to give2-amino-6-borono-2-[1-acetylpiperidin-4-yl]hexanoic acid hydrochloride(110 mg, 53%) as a white solid. ¹H NMR (D₂O, 400 MHz) δ 4.38 (bt, J=12Hz, 1H), 3.92 (bt, J=12 Hz, 1H), 3.03 (m, 1H), 2.55 (m, 1H), 2.11 (m,1H), 2.00 (s, 3H), 1.87-1.78 (m, 3H), 1.55 (m, 1H), 1.50-1.00 (m, 6H),0.68 (t, J=7.2 Hz, 2H). ESI⁺ MS found for C₁₃H₂₅BN₂O₅ m/z 583.3(2M−18+H), 565.6 (2M−2×18+H), 283.4 (M−18+H), 265.3 (M−2×18+H); ESI⁻ MSm/z 581.6 (2M−18−H), 299.4 (M−H), 281.4 (M−18−H).

Example 28-A: Preparation of2-amino-6-borono-2-{1-[(4-fluorophenyl)acetyl]-piperidin-4-yl}hexanoicacid hydrochloride

A solution of 4-fluorobenzeneacetic acid (126 mg, 0.816 mmol),N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (156 mg,0.816 mmol) and 1-hydroxybenzotriazole hydrate (125 mg, 0.816 mmol) indry DMF (4 mL) was stirred for 30 minutes under an atmosphere ofnitrogen. To the stirring solution was added a solution of crude2-amino-6-borono-2-(piperidin-4-yl)hexanoic acid dihydrochloride(Example 26-A, Step 1, 150 mg, 0.371 mmol) in dry DMF (4 mL) in oneportion. Triethylamine (0.31 mL, 2.23 mmol) was added and the resultingopaque mixture was stirred at room temperature for 1.75 hours. At theend of the reaction the solution was diluted with 1 N HCl and washedwith ethyl acetate (2×), prior to concentration of the combined organiclayers. The crude product was purified by reverse phase HPLC [PhenomenexLuna 250×30.00 mm, 10 micron column. 40 mL/min flow rate. Gradient:solvent A is 0.07% TFA in acetonitrile; solvent B is 0.10% TFA in water.Run 1—5% to 50% A over 24 min, then 50% to 100% A over 1 min. Run 2—5%to 40% A over 24 min, then 40% to 100% A over 1 min. Run 3—5% to 30% Aover 24 min, then 30% to 100% A over 1 min.] Product fractions werepooled and concentrated, and the residue was taken up in 0.5 N HCl (4mL)/acetonitrile (6 mL) and concentrated. The residue was once againtreated with 0.5 N HCl (4 mL)/acetonitrile (6 mL) and concentrated anddried under high vacuum overnight to give2-amino-6-borono-2-{1-[(4-fluorophenyl)acetyl]piperidin-4-yl}hexanoicacid hydrochloride (56 mg, 35%) as a white solid. ¹H NMR (MeOH-d₆, 400MHz) δ 7.28 (m, 2H), 7.07 (m, 2H), 4.69 (m, 1H), 4.15 (m, 1H), 3.78 (m,2H), 3.08 (m, 1H), 2.63 (m, 1H), 2.14 (m, 1H), 1.89 (m, 3H), 1.64 (m,1H), 1.45 (m, 4H), 1.30-0.95 (m, 2H), 0.84 (bt, J=6.8 Hz, 2H). ESI⁺ MSfound for C₁₉H₂₈BFN₂O₅ m/z 377.3 (M−18+H), 359.4 (M−2×18+H); ESI⁻ MS m/z393.4 (M−H), 375.4 (M−18−H).

Example 29-A: Preparation of2-amino-6-borono-2-{1-[(4-chlorophenyl)acetyl]-piperidin-4-yl}hexanoicacid hydrochloride

2-Amino-6-borono-2-{1-[(4-chlorophenyl)acetyl]-piperidin-4-yl}hexanoicacid hydrochloride is prepared in a manner analogous to that set forthin Example 28-A, except 4-chlorophenylacetic acid is used in place of4-fluorobenzeneacetic acid. ¹H NMR (MeOH-d₆, 400 MHz) δ 7.34 (m, 2H),7.25 (m, 2H), 4.70 (bd, J=13.2 Hz, 1H), 4.14 (bd, J=12.8 Hz, 1H), 3.79(m, 2H), 3.08 (m, 1H), 2.63 (m, 1H), 2.14 (m, 1H), 1.89 (m, 3H), 1.64(m, 1H), 1.45 (m, 4H), 1.30-0.95 (m, 2H), 0.84 (bt, J=6.8 Hz, 2H). ESI⁺MS found for C₁₉H₂₈BClN₂O₅ m/z 393.3 (M−18+H), 375.3 (M−2×18+H); ESI⁻ MSm/z 409.4 (M−H), 391.4 (M−18−H).

Example 30-A: Preparation of2-amino-6-borono-2-[1-benzoylpiperidin-4-yl]hexanoic acid hydrochloride

2-Amino-6-borono-2-[1-benzoylpiperidin-4-yl]hexanoic acid hydrochlorideis prepared in a manner analogous to that set forth in Example 28-A,except benzoic acid is used in place of 4-fluorobenzeneacetic acid. ¹HNMR (D₂O, 400 MHz) δ 7.41 (m, 3H), 7.30 (m, 2H), 4.53 (bt, J=12 Hz, 1H),3.72 (bt, J=12 Hz, 1H), 3.05 (m, 1H), 2.80 (m, 1H), 2.16 (bt, J=13 Hz,1H), 1.95 (m, 1H), 1.83 (m, 2H), 1.71 (m, 1H), 1.55-1.05 (m, 6H), 0.68(bt, J=7.2 Hz, 2H). ESI⁺ MS found for C₁₈H₂₇BN₂O₅ m/z 345.4 (M−18+H),327.4 (M−2×18+H); ESI⁻ MS m/z 361.4 (M−H), 343.4 (M−18−H).

Example 31-A: Preparation of2-amino-6-borono-2-{1-[(4-chlorobenzyl)carbamoyl]-piperidin-4-yl}hexanoicacid hydrochloride

A stirred solution of crude 2-amino-6-borono-2-(piperidin-4-yl)hexanoicacid dihydrochloride (Example 26-A, Step 1, 0.240 g, 0.594 mmol) in dryDMF (12 mL) under nitrogen was treated with triethylamine (0.662 mL,4.75 mmol) to give a white slurry. 1-chloro-4-(isocyanatomethyl)benzene(0.177 mL, 1.34 mmol) was added dropwise, and the resulting opaquemixture was stirred at room temperature for 1 h. The mixture was dilutedwith 1 N HCl (15 mL) and washed with ethyl acetate (2×20 mL), and theaqueous layer was concentrated under reduced pressure to give the crudeproduct which was purified by reverse phase HPLC [Phenomenex Luna250×30.00 mm, 10 micron column. 40 mL/min flow rate. Gradient: solvent Ais 0.07% TFA in acetonitrile; solvent B is 0.10% TFA in water; 5% to 50%A over 24 min, then 50% to 100% A over 1 min]. Product fractions werepooled and concentrated, and the residue was taken up in 0.5 N HCl (5mL)/acetonitrile (8 mL) and concentrated. The residue was once againtreated with 0.5 N HCl (5 mL)/acetonitrile (8 mL) and concentrated anddried under high vacuum overnight to give2-amino-6-borono-2-{1-[(4-chlorobenzyl)carbamoyl]-piperidin-4-yl}hexanoicacid hydrochloride (92 mg, 34%) as an off-white solid. ¹H NMR (D₂O, 400MHz) δ 7.26 (m, 2H), 7.15 (m, 2H), 4.19 (s, 2H), 3.95 (bt, J=14.6 Hz,2H), 2.75 (bt, J=12.8 Hz, 2H), 2.06 (bt, J=12.4 Hz, 1H), 1.81 (m, 3H),1.53 (bd, J=12.8 Hz, 1H), 1.32 (m, 4H), 1.11 (m, 2H), 0.69 (t, J=7.6 Hz,2H). ESI⁺ MS found for C₁₉H₂₉BClN₃O₅ m/z 408.4 (M−18+H); ESI⁻ MS m/z424.4 (M−H), 406.4 (M−18−H).

Example 32-A: Preparation of2-amino-6-borono-2-{1-[(4-chlorophenyl)-carbamoyl]piperidin-4-yl}hexanoicacid hydrochloride

2-Amino-6-borono-2-{1-[(4-chlorophenyl)carbamoyl]piperidin-4-yl}hexanoicacid hydrochloride is prepared in a manner analogous to that set forthin Example 31-A, except 1-chloro-4-isocyanatobenzene is used in place of1-chloro-4-(isocyanatomethyl)benzene. ¹H NMR (D₂O, 400 MHz) δ 7.25 (d,J=8 Hz, 2H), 7.09 (d, J=8 Hz, 2H), 4.07 (bt, J=14.4 Hz, 2H), 2.83 (bt,J=12.6 Hz, 2H), 2.08 (bt, J=12 Hz, 1H), 1.82 (m, 3H), 1.56 (bd, J=12.4Hz, 1H), 1.50-1.05 (m, 6H), 0.69 (t, J=7.6 Hz, 2H). ESI⁺ MS found forC₁₈H₂₇BClN₃O₅ m/z 394.3 (M−18+H), 376.3 (M−2×18+H); ESI⁻ MS m/z 410.4(M−H), 392.4 (M−18−H).

Example 33-A: Preparation of2-amino-6-borono-2-(1-{[2-(4-fluorophenyl)ethyl]-carbamoyl}piperidin-4-yl)hexanoicacid hydrochloride

2-Amino-6-borono-2-(1-{[2-(4-fluorophenyl)ethyl]carbamoyl}piperidin-4-yl)hexanoicacid hydrochloride is prepared in a manner analogous to that set forthin Example 31-A, except 4-fluorophenethyl isocyanate is used in place of1-chloro-4-(isocyanatomethyl)-benzene. ¹H NMR (D₂O, 400 MHz) δ 7.12 (dd,J=8 Hz, J₂=5.6 Hz, 2H), 6.97 (t, J=8.8 Hz, 2H), 3.80 (bt, J=12.8 Hz,2H), 3.27 (t, J=6.8 Hz, 2H), 2.65 (m, 4H), 1.99 (bt, J=12.8 Hz, 1H),1.81 (m, 2H), 1.73 (bd, J=12.8 Hz, 1H), 1.49 (bd, J=12.4 Hz, 1H),1.40-1.23 (m, 4H), 1.20-0.95 (m, 2H), 0.70 (t, J=7.6 Hz, 2H). ESI⁺ MSfound for C₂₀H₃₁BFN₃O₅ m/z 406.4 (M−18+H), 388.3 (M−2×18+H); ESI⁺ MS m/z422.5 (M−H), 404.5 (M−18−H).

Example 34-A: Preparation of2-amino-6-borono-2-(1-{[(4-chlorophenyl)amino]carbonothioyl}piperidin-4-yl)hexanoicacid hydrochloride

2-Amino-6-borono-2-(1-{[(4-chlorophenyl)amino]carbonothioyl}piperidin-4-yl)hexanoicacid hydrochloride is prepared in a manner analogous to that set forthin Example 31-A, except 4-chlorophenyl isothiocyanate is used in placeof 1-chloro-4-(isocyanatomethyl)-benzene and the clean product fractionsisolated from HPLC purification are handled in the following manner.Pooled fractions are concentration under reduced pressure at 35° C. toremove acetonitrile and frozen prior to lyophilization to remove water.The residue is taken up in ˜1 N HCl (10 mL) and frozen and lyophilized.Once again, the residue is taken up in ˜1 N HCl (10 mL) and frozen andlyophilized to give the title compound. ¹H NMR (D₂O, 400 MHz) δ 7.31 (d,J=8.9 Hz, 2H), 7.08 (d, J=8.8 Hz, 2H), 4.70 (m, 2H), 3.08 (bt, J=13.2Hz, 2H), 2.20 (bt, J=12.4 Hz, 1H), 1.87 (m, 3H), 1.65 (bd, J=13.2 Hz,1H), 1.53 (qd, J₁=12.8 Hz, J₂=3.6 Hz, 1H), 1.33 (m, 4H), 1.14 (m, 1H),0.70 (t, J=7.6 Hz, 2H). ESI⁺ MS found for C₁₈H₂₇BClN₃O₄S m/z 410.4(M−18+H); ESI⁻ MS m/z 426.5 (M−H), 408.4 (M−18−H).

Example 35-A: Preparation of2-amino-6-borono-2-((S)-1-(4-chlorophenylcarbamothioyl)-pyrrolidin-3-yl)hexanoicacid hydrochloride

Step 1: tert-Butyl(3R)-3-[methoxy(methyl)carbamoyl]pyrrolidine-1-carboxylate

In a 500 mL round-bottomed flask under a positive pressure of nitrogen,was added a methylene chloride (125 mL) solution of(R)—N-Boc-pyrroldine-3-carboxylic acid (7.00 g, 0.0325 mol). Thissolution was cooled to 0° C. using an ice/water bath and treatedsequentially with, N-(3-dimethylaminopropyl)-N′-ethylcarbodiimidehydrochloride (7.48 g, 0.0390 mol) and 1-hydroxybenzotriazole (5.29 g,0.0391 mol) in single portions. Following the addition of the couplingagents, the reaction mixture became cloudy, but upon further stirring aclear solution was obtained. The reaction mixture was stirred at 0° C.for 20 min then charged with N,O-dimethylhydroxylamine hydrochloride(4.78 g, 0.0490 mol) and triethylamine (13.5 mL, 0.0968 mol). Thecooling bath was removed and the reaction mixture was allowed to warm toroom temperature with stirring over a period of 1 h. The resultingsolution was diluted with dichloromethane (600 mL) and 1 N HCl (1000mL), mixed thoroughly and separated. The organic layer was washed withsaturated aqueous sodium bicarbonate (300 mL) and saturated aqueoussodium chloride (300 mL), then dried over Na₂SO₄, filtered andconcentrated to give tert-butyl(3R)-3-[methoxy(methyl)carbamoyl]pyrrolidine-1-carboxylate as acolorless oil (7.00 g; 83%). ¹H NMR (400 MHz, CDCl₃) δ 3.73 (s, 3H),3.60-3.37 (m, 4H), 3.21 (s, 3H), 2.35-2.09 (m, 3H) 1.47 (s, 9H); ESI MSfound for C₁₂H₂₂N₂O₄ m/z [159.1 (M+1-Boc)]

Step 2: tert-Butyl (3R)-3-hex-5-enoylpyrrolidine-1-carboxylate

In a 500 mL single necked round bottomed flask, a solution of tert-butyl(3R)-3-[methoxy(methyl)carbamoyl]pyrrolidine-1-carboxylate (7.00 g, 27.1mmol) in tetrahydrofuran (100 mL) was cooled to 0° C. and treated with0.5 M THF solution of 3-butenylmagnesium bromide (130 mL, 65 mmol) via apressure equalizing addition funnel over a period of 20 minutes. Oncethe addition was complete, the cooling bath was removed and the mixturewas allowed to warm to room temperature and stir for an additional 4 h.The reaction mixture was carefully quenched with 1 N HCl (300 mL) andstirred for an additional 20 min. The aqueous layer was extracted withethyl acetate (3×200 mL) and the combined organic layers were dried overNa₂SO₄, filtered and concentrated to a yellow oil. Purification of thecrude product by flash column chromatography (silica gel, 10% ethylacetate in hexanes) afforded tert-butyl(3R)-3-hex-5-enoylpyrrolidine-1-carboxylate (6.62 g; 96%) as a lightyellow oil. ¹H NMR (400 MHz, CDCl₃) δ 5.73-5.69 (m, 1H), 4.99-4.91 (m,2H), 3.61-3.42 (m, 2H), 3.13-3.05 (m, 1H), 2.50 (t, J=7.2 Hz, 2H), 2.26(q, J=7.2 Hz, 2H), 2.11-1.90 (m, 3H), 1.38 (s, 9H); ESI MS found forC₁₄H₂₃NO₃ m/z [154.1 (M+1-Boc)].

Step 3:2-Acetamido-N-tert-butyl-2-[(3R)-1-tert-butylcarboxylpyrrolidin-3-yl]hex-5-enamide

A solution of tert-butyl (3R)-3-hex-5-enoylpyrrolidine-1-carboxylate(1.00 g, 3.95 mmol), ammonium acetate (761 mg, 9.87 mmol) and tert-butylisocyanide (2 mL, 30 mmol) in 2,2,2-trifluoroethanol (2 mL) was sealedin a 10 mL microwave vial. The reaction mixture was irradiated in a CEMmicrowave at 85° C. for 1.5 h. After cooling to room temperature, thesolution was diluted with ethyl acetate (75 mL) and washed withsaturated aqueous sodium bicarbonate (30 mL), water (30 ml) andsaturated aqueous sodium chloride (30 ml). The organic layer was driedover Na₂SO₄, filtered and concentrated. Purification by flash columnchromatography (silica gel, eluting with 20% ethyl acetate in hexanes)afforded recovered starting material (0.265 g, 27%) and2-acetamido-N-tert-butyl-2-[(3R)-1-tert-butylcarboxylpyrrolidin-3-yl]hex-5-enamideas a mixture of diastereomers (1.06 g, 68%); ESI MS found for C₂₁H₃₇N₃O₄m/z.

Step 4: ten-butyl(3R)-3-[1-acetamido-1-(tert-butylcarbamoyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pentyl]pyrrolidine-1-carboxylate

In a 50 mL round bottomed flask a solution ofbis(1,5-cyclooctadiene)diiridium(I) dichloride (92 mg, 0.14 mmol) and1,2-bis(diphenylphosphino)ethane (117 mg, 0.294 mmol) in tetrahydrofuran(12 mL) was stirred for 5 min prior to cooling to 0° C. using anice/water bath. After 15 min, 4,4,5,5-tetramethyl-1,3,2-dioxaborolane(600 uL, 4 mmol) was added in a single portion via syringe. After anadditional 5 min at 0° C. the solution was warmed to room temperatureand stirred for an additional 15 min. The reaction was then cooled oncemore in an ice/water bath and stirred for 10 min. From a separate flask,a THF solution (4 mL) of2-acetamido-N-tert-butyl-2-[(3R)-1-tert-butylcarboxylpyrrolidin-3-yl]hex-5-enamide(1.06 g, 2.68 mmol) in tetrahydrofuran (4 mL) was transferred viasyringe into the reaction mixture while it continued to stir at 0° C.for 10 minutes. The cold reaction mixture is then allowed to warm toroom temperature and stirred for an additional 4 hours, prior toquenching the reaction by pouring it into a solution of saturatedaqueous sodium bicarbonate (20 mL) and ethyl acetate (20 mL). Afterextraction, the organic layer was separated and the aqueous layer wasfurther extracted using ethyl acetate (2×20 mL). The combined organicextracts were dried over Na₂SO₄, filtered and concentrated to affordtert-butyl(3R)-3-[1-acetamido-1-(tert-butylcarbamoyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pentyl]pyrrolidine-1-carboxylate(1.46 g) as an oil, which was used without additional purification. ESIMS found for C₂₇H₅₀BN₃O₆ m/z 524.5 (M+H)⁺; 522.7 (M−H)⁻.

Step 5: (R)-2-amino-6-borono-2-((R)-pyrrolidin-3-yl)hexanoic acid

In a 50 mL round bottom flask, tert-butyl(3R)-3-[1-acetamido-1-(tert-butylcarbamoyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pentyl]pyrrolidine-1-carboxylate(1.41 g, 2.69 mmol) was dissolved in 1,4-dioxane (10 mL). To thissolution was added a 6M aqueous solution of hydrogen chloride (10 mL) ina single portion and the reaction was heated under refluxing conditionsfor 18 h. At the end of 18 hours the reaction mixture was cooled to roomtemperature prior to dilution with water (10 mL). The aqueous layer waswashed with ethyl acetate (20 mL) and concentrated in vacuo prior tolyophilization to afford(R)-2-amino-6-borono-2-((R)-pyrrolidin-3-yl)hexanoic aciddihydrochloride (0.657 g) as a mixture of diastereomers. The crude foamwas used without purification in the next step. ESI MS found forC₁₀H₂₁BN₂O₄ m/z 227.2 (M+H-water)⁺.

Step 6:2-amino-6-borono-2-((S)-1-(4-chlorophenylcarbamothioyl)pyrrolidin-3-yl)hexanoicacid hydrochloride

A solution of (R)-2-amino-6-borono-2-((R)-pyrrolidin-3-yl)hexanoic acid(200 mg, 0.8 mmol) and triethylamine (700 mg, 6 mmol) inN,N-dimethylformamide (4 mL, 50 mmol) was treated with 4-chlorophenylisothiocyanate (300 mg, 1.8 mmol) in a single portion. After stirring atroom temperature for 30 min, the reaction was diluted with 1 N HCl (20mL) and washed with ethyl acetate (20 mL). The aqueous solution wasconcentrated and purified by HPLC to give2-amino-6-borono-2-((S)-1-(4-chlorophenylcarbamothioyl)pyrrolidin-3-yl)hexanoicacid hydrochloride hydrochloride (81 mg, 20%). ¹H NMR (400 MHz, D₂O,Mixture of diastereoisomers) δ 7.40-7.23 (m, 4H), 4.29-3.46 (m, 4H),2.95-2.81 (m, 1H), 2.41-1.76 (m, 4H), 1.58-1.40 (br. m, 2H), 1.36-1.20(br, m, 1H), 0.90-0.80 (br. m, 2H); MS ESI found for C₁₇H₂₅BClN₃O₄S m/z(M-water+H)⁺396.2; MS (ESI−) m/z (M−H)^(˜)412.3, (M-water−H)⁻ 394.3

Example 36-A: Preparation of2-amino-6-borono-2-((S)-1-(4-chlorophenylcarbamoyl)pyrrolidin-3-yl)hexanoicacid hydrochloride

A solution of (R)-2-amino-6-borono-2-((R)-pyrrolidin-3-yl)hexanoic acid(Example 35-A, Step 5, 200 mg, 0.8 mmol) and triethylamine (900 uL, 6mmol) in N,N-dimethylformamide (4 mL, 50 mmol) was treated with4-chlorobenzene isocyanate- (280 mg, 1.8 mmol) in a single portion.After stirring at room temperature for 30 min, the reaction was dilutedwith 1 N HCl (20 mL) and washed with ethyl acetate (20 mL). The aqueoussolution was concentrated and purified by HPLC to give2-amino-6-borono-2-((S)-1-(4-chlorophenylcarbamoyl)pyrrolidin-3-yl)hexanoicacid (0.021 g, 6%). ¹H NMR (400 MHz, D₂O, Mixture of diastereoisomers) δ7.26 (d, J=8.1 Hz, 2H), 7.14 (d, J=8.1 Hz, 2H), 3.70-3.48 (br, m, 2H),3.99-3.08 (br, m, 2H), 2.79-2.65 (br, m, 1H), 2.30-1.75 (br. m, 4H),1.54-1.44 (br. m, 2H), 1.35-1.27 (br. m, 1H), 0.87 (t, J=6.5 Hz, 2H); MS(ESI+) found for C₁₇H₂₅C₁BN₃O₅ m/z (M-water+H)⁺ 380.2; MS; (M-water+Na)⁺403.3

Example 37-A: Preparation2-amino-6-borono-2-((S)-1-(4-fluorobenzl)pyrrolidin-3-yl)hexanoic aciddihydrochloride

Step 1: 2-acetamido-N-tert-butyl-2-((R)-pyrrolidin-3-yl)hex-5-enamide

To a 100 mL round bottomed flask containing a solution of2-acetamido-N-tert-butyl-2-[(3R)-1-tert-butylcarboxylpyrrolidin-3-yl]hex-5-enamide(Example 35-A, Step 3, 1.42 g, 3.59 mmol) in methylene chloride (20 mL,300 mmol) was added trifluoroacetic acid (2.4 mL, 31 mmol) in a singleportion via syringe. After stirring for 4 h, the solution was pouredinto saturated aqueous sodium bicarbonate (100 mL) and the aqueous layerwas extracted with 10% TFE in DCM (2×50 mL). The combined organicextracts were dried over Na₂SO₄, filtered and concentrated to give2-acetamido-N-tert-butyl-2-[(3R)-pyrrolidin-3-yl]hex-5-enamide (0.95 g,90%) as a light yellow oil. Used without further purification insubsequent step. ¹H NMR (400 MHz, CDCl₃, Mixture of diastereoisomers) δ7.80 (br. s, 0.5H), 7.60 (br. s, 0.5H), 7.45 (br. s, 0.5H), 1.96-165(br. s, 0.5H), 1.80-1.55 (m, 4H), 1.36-1.34 (2×s, 9H), ESI MS found forC₁₆H₂₉N₃O₂ m/z 296.3 (M+H)⁺.

Step 2:2-acetamido-N-tert-butyl-2-((R)-1-(4-fluorobenzyl)pyrrolidin-3-yl)hex-5-enamide

A solution of2-acetamido-N-tert-butyl-2-[(3R)-pyrrolidin-3-yl]hex-5-enamide (315 mg,1.07 mmol), 4-fluorobenzaldehyde (140 uL, 1.3 mmol) and acetic acid (60uL, 1 mmol) in methylene chloride (10 mL, 200 mmol) was stirred for 10minutes prior to the addition of sodium triacetoxyborohydride (377 mg,1.78 mmol) in a single portion. After stirring at room temperatureovernight, the reaction was quenched with 1 N NaOH (10 mL). The organiclayer thus obtained was separated and the aqueous layer furtherextracted with DCM (3×10 mL). The combined organic extracts were driedover Na₂SO₄, filtered and concentrated to give2-acetamido-N-tert-butyl-2-((R)-1-(4-fluorobenzyl)pyrrolidin-3-yl)hex-5-enamide(0.387 g, 89.9%) as an oil. The oil was used in the next step withoutpurification. ESI MS found for C₂₃H₃₄FN₃O₂ m/z 404.3 (M+H)⁺.

Step 3:2-acetamido-N-tert-butyl-2-((R)-1-(4-fluorobenzyl)pyrrolidin-3-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A solution of bis(1,5-cyclooctadiene)diiridium(I) dichloride (35.0 mg,0.0520 mmol) and 1,2-bis(diphenylphosphino)-ethane (44 mg, 0.11 mmol) intetrahydrofuran (5 mL, 60 mmol) was cooled to 0° C. After stirring for10 min 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (120 uL, 0.83 mmol) wasadded in a single portion via syringe and the reaction mixture wasstirred at 0° C. for 5 min before warming to room temperature andstirring an additional 15 min. The reaction mixture was recooled to 0°C. and treated with2-acetamido-N-tert-butyl-2-[(3R)-1-(4-fluorobenzyl)pyrrolidin-3-yl]hex-5-enamide(210 mg, 0.52 mmol) in tetrahydrofuran (3 mL, 40 mmol) in a singleportion. After stirring for 10 min at 0° C., the reaction was warmed toroom temperature and stirred an additional 4 h. The mixture was dilutedwith aqueous sodium bicarbonate, extracted with DCM (3×50 mL), driedover Na₂SO₄, filtered and concentrated to give2-acetamido-N-tert-butyl-2-((R)-1-(4-fluorobenzyl)pyrrolidin-3-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamideas a light orange oil that was used without further purification. ESI MSfound for C₂₉H₄₇BFN₃O₄ m/z 532.3 (M+H)⁺

Step 4:2-amino-6-borono-2-((R)-1-(4-fluorobenzyl)pyrrolidin-3-yl)hexanoic aciddihydrochloride

An aqueous solution of2-acetamido-N-tert-butyl-2-((R)-1-(4-fluorobenzyl)pyrrolidin-3-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(0.280 g, 0.527 mmol) in 6M hydrogen chloride (10 mL, 60 mmol) washeated under reflux overnight. The reaction was cooled to roomtemperature, diluted with 20 mL of water, and washed with ethyl acetate(20 mL). The aqueous layer was purified by HPLC (3 injections) using a5-20% acetonitrile in water. The fractions corresponding to the desiredproduct were concentrated and lyophilized to give2-amino-6-borono-2-((R)-1-(4-fluorobenzyl)pyrrolidin-3-yl)hexanoic aciddihydrochloride as white powder, which became oily upon exposure to air(hydroscopic). (0.003 g, 2%). ¹H NMR (400 MHz, CDCl₃, Mixture ofdiastereoisomers) δ 7.41 (dd, J₁=8.1 Hz, J₂=6.5 Hz, 2H), 7.12 (t, J=8.1Hz, 2H), 4.35-4.25 (br, m, 2H), 3.77-3.09 (br. m, 3H), 2.99-2.60 (br. m,1H), 2.39-1.57 (br. m, 4H), 1.34-1.18 (br. m, 2H), 1.15-1.03 (br. m,1H), 0.70-0.61 (m, 2H); ESI MS found for C₁₇H₂₆BFN₂O₄ m/z 335.3(M+H-water)⁺; 351.4 (M−H)⁻; 333.4 (M+H-water)⁻.

Example 38-A: Preparation of2-amino-6-borono-2-((R)-1-(4-(trifluoromethyl)benzyl)pyrrolidin-3-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-((R)-1-(4-(trifluoromethyl)benzyl)pyrrolidin-3-yl)hexanoicacid was prepared in a manner analogous to that set forth in Example37-A except that 4-trifluoromethylbenzaldehyde was used in step 2. ¹HNMR (400 MHz, D₂O, Mixture of diastereoisomers) δ 7.73 (d, J=8.1 Hz,2H), 7.58 (d, J=8.1 Hz, 2H), 4.41 (s, 2H), 2.82-3.63 (m, 4H), 2.42-1.58(m, 4H), 1.38-1.20 (m, 2H), 1.18-1.03 (m, 1H), 0.72-0.63 (m, 2H); ESI MSfound for C₁₈H₂₆BF₃N₂O₄ m/z 385.3 (M+H-water)⁺; 401.4 (M−H)⁻; 383.4(M−H-water)⁻.

Example 39-A: Preparation of2-amino-6-borono-2-OR)-1-(4-methylbenzyl)pyrrolidin-3-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-((R)-1-(4-methylbenzyl)pyrrolidin-3-yl)hexanoic aciddihydrochloride was prepared in a manner analogous to that set forth inExample 37-A except that 4-methylbenzaldehyde was used in step 2 ¹H NMR(400 MHz, D₂O, mixture of diastereoisomers) δ 7.22 (d, J=8.1 Hz, 2H),7.18 (d, J=8.1 Hz, 2H), 4.30-4.11 (m, 2H), 3.69-3.28 (m, 3H), 3.24-2.66(m, 2H), 2.33-2.02 (m, 4H), 1.92-1.55 (m, 3H), 1.34-1.17 (m, 2H),1.15-1.00 (m, 1H), 0.67-0.57 (m, 2H); ESI MS found for C₁₈H₂₉BN₂O₄ m/z349.5 (M+H)⁺; 331.4 (M+H-water)⁺; 347.5 (M−H)⁻; 329.4 (M−H-water)⁻.

Example 40-A: Preparation of2-amino-6-borono-2-((R)-1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)hexanoicacid

Step 1: (R)-1-(1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)pent-4-en-1-one

To a solution of (R)-tert-butyl 3-pent-4-enoylpyrrolidine-1-carboxylate(300 mg, 1 mmol) in methylene chloride (5 mL, 80 mmol) was addedtrifluoroacetic acid (2 mL, 20 mmol) and the resultant mixture wasstirred at room temperature for 1 h. The crude reaction mixture was thenconcentrated to obtain a crude oil which was re-dissolved in methylenechloride (5 mL, 80 mmol) prior to the addition of triethylamine (1 mL, 7mmol). This solution was cooled to 0° C. before adding2-nitrobenzenesulfonyl chloride (450 mg, 2.0 mmol) in a single portion.The reaction mixture, which immediately turned blue in color, wasstirred overnight at room temperature. At the end of the reaction, thesolution was diluted with saturated aqueous sodium bicarbonate (50 mL)to give two layers which were separated. The aqueous layer was furtherextracted with methylene chloride (2×20 mL) and the combined organiclayers were dried over Na₂SO₄, filtered and concentrated to give a blueoil, which was purified by flash column chromatography (silica gel,eluting with 0-100% ethyl acetate in hexanes) to give(R)-1-(1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)pent-4-en-1-one (305 mg,80%). ¹H NMR (400 MHz, CDCl₃) δ 8.07-8.03 (m, 1H), 7.76-7.70 (m, 2H),7.66-7.62 (m, 1H), 5.78 (ddt, J₁=17.0 Hz, J₂=10.4 Hz, J₃=6.5 Hz, 1H),5.07-4.97 (m, 2H), 3.70 (dd, J₁=12.0 Hz, J₂=8.0 Hz, 1H) 3.61 (dd,J₁=12.0 Hz, J₂=8.1 Hz, 1H), 3.52 (t, J=8.1 Hz, 2H), 3.24 (p, J=8.0 Hz,1H), 2.59 (td, J₁=7.3 Hz, J₂=3.6 Hz, 2H), 2.32 (q, J=6.8 Hz, 2H),2.24-2.16 (m, 1H), 2.14-2.05 (m, 1H), 1.28 (ddd, J₁=17.8 Hz, J₂=10.6 Hz,J₃=7.3 Hz, 1H); ESI MS found for C₁₅H₁₈N₂O₅S m/z 339.3 (M+H)⁺.

Step 2:2-acetamido-N-tert-butyl-2-((R)-1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)hex-5-enamide

A solution of(R)-1-(1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)pent-4-en-1-one (1.03 g,3.04 mmol) and ammonium acetate (0.548 g, 7.11 mmol) in2,2,2-trifluoroethanol (1.5 mL, 2.0 mmol) was treated with tert-butylisocyanide (1.5 mL, 24 mmol) followed by stirring at room temperature.After 8 hours, an additional 0.5 mL of isocyanate was added and thetemperature of the reaction was increased to 40° C. After stirringovernight at 40° C., the crude reaction was partitioned between ethylacetate and saturated aqueous sodium bicarbonate. The organic layer wasseparated, dried over Na₂SO₄, filtered and concentrated prior topurification of the crude oil by flash column chromatography (silicagel, using 0-100% ethyl acetate in hexanes) to give2-acetamido-N-tert-butyl-2-((R)-1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)hex-5-enamide(1.00 g, 68.4%) as a brown foam. ¹H NMR (400 MHz, CDCl₃, mixture ofdiastereoisomers) δ 8.07-8.02 (m, 1H), 7.81-7.71 (m, 2H), 7.64-7.59 (m,1H), 6.85 (2×s, 1H), 5.98-5.63 (br, m, 2H), 5.06-4.95 (m, 2H), 3.61-2.90(m, 6H), 2.02-2.00 (2×s, 3H), 1.95-1.41 (m, 5H), 1.38-1.36 (2×s, 9H);ESI MS found for C₂₂H₃₂N₄O₆S m/z 481.2 (M+H)⁺; 479.3 (M−H)⁻.

Step 3:2-acetamido-N-tert-butyl-2-((R)-1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

In a 50 mL round bottomed flask, a solution ofbis(1,5-cyclooctadiene)diiridium(I) dichloride (72 mg, 0.11 mmol) and1,2-bis(diphenylphosphino)-ethane (84 mg, 0.21 mmol) in tetrahydrofuran(10 mL, 100 mmol) was cooled to 0° C., stirred for 15 min and treatedwith 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (450 uL, 3.1 mmol). Afteradditional stirring for 5 min the cooling bath was removed and thereaction mixture was allowed to warm to room temperature with stirring aperiod of 15 min. The reaction mixture was then recooled to 0° C. andtreated with a solution of2-acetamido-N-tert-butyl-2-((R)-1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)hex-5-enamide(1.00 g, 2.08 mmol) in tetrahydrofuran (2 mL, 20 mmol) added in adropwise manner via syringe. After stirring for 5 min at 0° C. thereaction was warmed to room temperature and stirred until the desiredproduct was obtained in good yield. The reaction mixture was quenched bypouring the crude into a saturated solution of aqueous sodium carbonate(50 mL). The aqueous layer was extracted using ethyl acetate (3×30 mL),and the combined organic layers were washed with saturated aqueoussodium chloride (20 mL), dried over Na₂SO₄, filtered and concentrated togive2-acetamido-N-tert-butyl-2-((R)-1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(1.20 g, 94.8%) as a foam. The titled compound was used without furtherpurification. ESI MS found for C₂₈H₄₅N₄O₈BS m/z 609.5 (M+H)⁺; 607.5(M−H)⁻.

Step 4:2-amino-6-borono-2-((R)-1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)hexanoicacid

A solution of2-acetamido-N-tert-butyl-2-((R)-1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(500 mg, 0.8 mmol) in 1,4-dioxane (3 mL, 40 mmol) was treated with a 6Maqueous solution of hydrogen chloride (6 mL, 40 mmol) followed byheating to 100° C. for 24 h. At the end of the 24 hour period, thereaction mixture was diluted with water and filtered. The filtrate thatwas obtained was purified by HPLC using 5%-50% acetonitrile in waterover 30 min. The product-containing fractions were concentrated, thendissolved in 1N HCl and frozen prior to lyophilization to afford2-amino-6-borono-2-((R)-1-(2-nitrophenylsulfonyl)pyrrolidin-3-yl)hexanoicacid (79 mg, 20%) as a white foam. ¹H NMR (400 MHz, DMSO-d₆, Mixture ofdiastereoisomers) δ 8.55-8.35 (2H), 8.05-7.98 (m, 2H), 7.96-7.85 (m,2H), 5.83 (t, J=6.5 Hz, 2H), 3.70-3.14 (m, 4H), 2.78-2.65 (m, 1H),2.19-1.60 (m, 4H), 1.47-1.23 (m, 3H), 1.14-1.00 (m, 1H); ESI MS foundfor C₁₆H₂₄BN₃O₈S m/z 412.1 [M-OH)⁺; 410.2 (M−H₂O)⁻.

Example 41-A: Preparation of2-amino-6-borono-2-(1-phenethylpiperidin-4-yl)hexanoic acid

2-Amino-6-borono-2-(1-phenethylpiperidin-4-yl)hexanoic acid is preparedin a manner analogous to that set forth in Example 118, except3-phenylethanal is used as the aldehyde in step 6. ¹H NMR (D₂O, 300 MHz)δ 7.35-7.28 (m, 2H), 7.30-7.20 (m, 3H), 3.71-3.62 (m, 2H), 3.35-3.25 (m,2H), 3.04-2.90 (m, 4H), 2.2-2.05 (m, 2H), 1.93-1.75 (m, 4H), 1.55-1.45(m, 1H), 1.38-1.22 (m, 3H), 1.18-1.05 (m, 1H), 0.69 (t, J=7.2 Hz, 2H).ESI MS found for C₁₉H₃₁BN₂O₄ m/z [363.2 (M+1)].

Example 42-A: Preparation of2-amino-6-borono-2-(1-(3,4-dichlorophenylcarbamoyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-(3,4-dichlorophenylcarbamoyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example31-A, except that 1,2-dichloro-4-isocyanatobenzene is used as theisocyanate. ¹H NMR (D₂O, 500 MHz) δ 7.33-7.25 (m, 2H), 7.01-6.96 (m,1H), 4.01 (t, J=11.4 Hz, 2H), 2.80 (t, J=11.1 Hz, 2H), 2.08-2.01 (m,1H), 1.83-1.77 (m, 3H), 1.58-1.51 (m, 1H), 1.47-1.32 (m, 1H), 1.33-1.18(m, 3H), 1.18-1.04 (m, 2H), 0.65 (t, J=7.2 Hz, 2H). ESI MS found forC₁₈H₂₇BCl₂N₃O₅ m/z [428.5 (M−18+1)].

Example 43-A: Preparation of2-amino-6-borono-2-(1-(4-chlorobenzylcarbamothioyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-(4-chlorobenzylcarbamothioyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example31-A, except that 1-chloro-4-(isothiocyanatomethyl)benzene is used asthe isocyanate. ¹H NMR (D₂O, 300 MHz) δ 7.21 (d, J=8.4 Hz, 2H), 7.09 (d,J=8.4 Hz, 2H), 4.62 (bs, 2H), 4.59 (m, 2H), 2.95 (bt, J=11.4 Hz, 2H),2.14 (bt, J=11.4 Hz, 1H), 1.85-1.70 (m, 3H), 1.62-1.51 (m, 1H),1.48-1.00 (m, 6H), 0.63 (t, J=7.5 Hz, 2H). ESI MS found forC₁₉H₂₉BClN₃O₄S m/z [442.6 (M+1)].

Example 44-A: Preparation of2-amino-6-borono-2-(1-(3-chloro-4-methylphenylcarbamothioyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-(3-chloro-4-methylphenylcarbamothioyl)piperidin-4-yl)hexanoicacid was prepared in a manner analogous to that set forth in Example32-A, except that 2-chloro-4-isothiocyanato-1-methylbenzene is used asthe isocyanate.

Example 45-A: Preparation of2-amino-6-borono-2-(1-(naphthalen-1-ylcarbamothioyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-(naphthalen-1-ylcarbamothioyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example32-A, except that 1-isothiocyanatonaphthalene is used as the isocyanate.¹H NMR (D₂O, 300 MHz) δ 7.87-7.78 (m, 2H), 7.70-7.64 (m, 1H), 7.46-7.37(m, 3H), 7.22-7.17 (m, 1H), 4.60-4.55 (m, 2H), 3.06 (bt, J=11.4 Hz, 2H),2.20 (bt, J=11.4 Hz, 1H), 1.92-1.76 (m, 3H), 1.70-1.50 (m, 2H),1.40-1.20 (m, 4H), 1.18-1.03 (m, 1H), 0.67 (t, J=7.2 Hz, 2H). ESI MSfound for C₂₂H₃₀BN₃O₄S m/z [444.6 (M+1)].

Example 46-A: Preparation of2-amino-6-borono-2-(1-(3-(4-chlorophenyl)propyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-(3-(4-chlorophenyl)propyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 3-(4-chlorophenyl)propanal is used as the aldehyde in step6. ¹H NMR (D₂O, 300 MHz) δ 7.16 (d, J=8.4 Hz, 2H), 7.04 (d, J=8.4 Hz,2H), 3.54-3.45 (m, 2H), 2.97-2.88 (m, 2H), 2.87-2.72 (m, 2H), 2.58-2.50(m, 2H), 2.10-1.95 (m, 1H), 1.96-1.85 (m, 1H), 1.88-1.62 (m, 6H),1.48-1.32 (m, 1H), 1.30-1.15 (m, 3H), 1.09-0.98 (m, 1H), 0.60 (t, J=7.2Hz, 2H). ESI MS found for C₂₀H₃₂BClN₂O₄ m/z [393.6 (M−18+1)].

Example 47-A: Preparation of2-amino-6-borono-2-(1-(2,4-dichlorophenethyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-(2,4-dichlorophenethyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 2-(2,4-dichlorophenyl)acetaldehyde is used as the aldehydein step 6. ¹H NMR (D₂O, 500 MHz) δ 7.41 (s, 1H), 7.20 (bs, 2H),3.26-3.17 (m, 2H), 3.09-3.01 (m, 2H), 3.00-2.89 (m, 2H), 2.11-2.02 (m,2H), 1.88-1.70 (m, 4H), 1.51-1.42 (m, 1H), 1.34-1.20 (m, 3H), 1.12-1.02(m, 1H), 0.67 (t, J=7.2 Hz, 2H). ESI MS found for C₁₉H₂₉BCl₂N₂O₄ m/z[413.6 (M−18+1)].

Example 48-A: Preparation of2-amino-6-borono-2-(1-(3,4-difluorobenzyl)piperidin-4-yl)hexanoic acid

2-Amino-6-borono-2-(1-(3,4-difluorobenzyl)piperidin-4-yl)hexanoic acidis prepared in a manner analogous to that set forth in Example 118,except that 3,4-difluorobenzaldehyde is used as the aldehyde in step 6.¹H NMR (D₂O, 300 MHz) δ 7.35-7.05 (m, 3H), 4.14 (s, 2H), 3.50-3.36 (m,2H), 2.94-2.84 (m, 2H), 2.16-1.95 (m, 2H), 1.86-1.54 (m, 4H), 1.50-1.35(m, 1H), 1.36-1.14 (m, 3H), 1.14-0.97 (m, 1H), 0.65 (t, J=7.2 Hz, 2H).ESI MS found for C₁₈H₂₇BF₂N₂O₄ m/z [385.1 (M+1)].

Example 49-A: Preparation of2-amino-6-borono-2-(1-(4-chloro-3-fluorobenzyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-(4-chloro-3-fluorobenzyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except 4-chloro-3-fluoro benzaldehyde is used as the aldehyde in step 6.¹H NMR (D₂O, 300 MHz) δ 7.51-7.43 (m, 1H), 7.32-7.23 (m, 1H), 7.22-7.10(m, 1H), 4.13 (s, 2H), 3.51-3.38 (m, 2H), 2.98-2.82 (m, 2H), 2.18-1.94(m, 2H), 1.88-1.61 (m, 4H), 1.50-1.32 (m, 1H), 1.33-1.14 (m, 3H),1.13-0.96 (m, 1H), 0.61 (t, J=7.2 Hz, 2H). ESI MS found forC₁₈H₂₇BClFN₂O₄ m/z [401.2 (M+1)].

Example 50-A: Preparation of2-amino-6-borono-2-(1-(3-(3-chloro-5-fluorophenyl)propyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-(3-(3-chloro-5-fluorophenyl)propyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 3-(3-chloro-5-fluorophenyl)propanal is used as the aldehydein step 6. ¹H NMR (D₂O, 300 MHz) δ 7.01-6.91 (m, 2H), 6.86-6.78 (m, 1H),3.55-3.45 (m, 2H), 2.97-2.85 (m, 2H), 2.86-2.74 (m, 2H), 2.60-2.49 (m,2H), 2.09-1.60 (m, 8H), 1.48-1.35 (m, 1H), 1.35-1.15 (m, 3H), 1.10-0.97(m, 1H), 0.62 (t, J=7.5 Hz, 2H). ESI MS found for C₂₀H₃₁BClFN₂O₄ m/z[429.5 (M+1)].

Example 51-A: Preparation of2-amino-6-borono-2-(1-((4-fluoronaphthalen-1-yl)methyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-((4-fluoronaphthalen-1-yl)methyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 4-fluoro-1-naphthaldehyde is used as the aldehyde in step 6.¹H NMR (D₂O, 300 MHz) δ 8.03 (d, J=8.4 Hz, 1H), 7.95 (d, J=8.4 Hz, 1H),7.64-7.44 (m, 3H), 7.10 (t, J=8.4 Hz, 1H), 4.60 (bs, 2H), 3.51-3.40 (m,2H), 3.11-2.97 (m, 2H), 2.20-2.04 (m, 1H), 2.00-1.85 (m, 1H), 1.80-1.60(m, 4H), 1.46-1.31 (m, 1H), 1.30-1.10 (m, 3H), 1.10-0.95 (m, 1H), 0.59(t, J=7.2 Hz, 2H). ESI MS found for C₂₂H₃₀BFN₂O₄ m/z [417.1 (M+1)].

Example 52-A: Preparation of2-amino-6-borono-2-(1-(3-(2,4-difluorophenyl)propyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(3-(2,4-difluorophenyl)propyl)piperidin-4-yl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 118, except that 3-(2,4-difluorophenyl)propanal is used asthe aldehyde in step 6. ¹H NMR (D₂O, 500 MHz) δ 7.22-7.15 (m, 1),6.88-6.70 (m, 2H), 3.60-3.49 (m, 2H), 3.05-3.94 (m, 2H), 2.93-2.83 (m,2H), 2.66-2.58 (m, 2H), 2.15-2.02 (m, 2H), 1.98-1.70 (m, 6H), 1.50-1.41(m, 1H), 1.39-1.25 (m, 3H), 1.15-1.05 (m, 1H), 0.70 (t, J=7.2 Hz, 2H).ESI MS found for C₂₀H₃₁BF₂N₂O₄ m/z [395.7 (M+1−18)].

Example 53-A: Preparation of2-amino-6-borono-2-(1-(2-(trifluoromethyl)benzyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(2-(trifluoromethyl)benzyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 2-(trifluoromethyl)benzaldehyde is used as the aldehyde instep 6. ¹H NMR (D₂O, 300 MHz) δ 7.79-7.74 (m, 1H), 7.67-7.52 (m, 3H),4.39 (s, 2H), 3.62-3.48 (m, 2H), 3.14-3.00 (m, 2H), 2.15-1.95 (m, 2H),1.87-1.65 (m, 4H), 1.55-1.38 (m, 1H), 1.35-1.20 (m, 3H), 1.15-0.96 (m,1H), 0.65 (t, J=7.5 Hz, 2H). ESI MS found for C₁₉H₂₈BF₃N₂O₄ m/z [417.2(M+1)].

Example 54-A: Preparation of2-amino-6-borono-2-(1-(2-morpholinobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(2-morpholinobenzyl)piperidin-4-yl)hexanoic acidis prepared in a manner analogous to that set forth in Example 118,except that 2-morpholinobenzaldehyde is used as the aldehyde in step 6.¹H NMR (D₂O, 300 MHz) δ 7.43 (dd, J₁=8.7 Hz, J₂=1.5 Hz, 1H), 7.36-7.30(m, 2H), 7.18 (dd, J₁=8.4 Hz, J₂=1.2 Hz, 1H), 4.32 (s, 2H), 3.82-3.75(m, 4H), 3.55-3.45 (m, 2H), 3.10-2.95 (m, 2H), 3.90-3.82 (m, 4H),2.18-1.98 (m, 2H), 1.89-1.70 (m, 4H), 1.50-1.35 (m, 1H), 1.35-1.20 (m,3H), 1.15-0.99 (m, 1H), 0.64 (t, J=7.2 Hz, 2H). ESI MS found forC₂₂H₃₆BN₃O₅ m/z [434.1 (M+1)].

Example 55-A: Preparation of2-amino-2-(1-(biphenyl-2-ylmethyl)piperidin-4-yl)-6-boronohexanoic aciddihydrochloride

2-Amino-2-(1-(biphenyl-2-ylmethyl)piperidin-4-yl)-6-boronohexanoic acidis prepared in a manner analogous to that set forth in Example 118,except that biphenyl-2-carbaldehyde is used as the aldehyde in step 6.¹H NMR (D₂O, 300 MHz) δ 7.53-7.24 (m, 9H), 4.29 (s, 2H), 3.32-3.18 (m,2H), 2.58-2.42 (m, 2H), 1.90-1.75 (m, 2H), 1.73-1.52 (m, 4H), 1.52-1.48(m, 1H), 1.35-1.10 (m, 3H), 1.10-0.95 (m, 1H), 0.62 (t, J=7.2 Hz, 2H).ESI MS found for C₂₄H₃₃BN₂O₄ m/z [425.2 (M+1)].

Example 56-A: Preparation of2-amino-6-borono-2-(1-(quinolin-8-ylmethyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(quinolin-8-ylmethyl)piperidin-4-yl)hexanoic acidis prepared in a manner analogous to that set forth in Example 118,except that quinoline-8-carbaldehyde is used as the aldehyde in step 6.¹H NMR (D₂O, 300 MHz) δ 8.98 (bd, J=4.3 Hz, 1H), 8.82 (d, J=8.2 Hz, 1H),8.21 (d, J=8.4 Hz, 1H), 8.04 (d, J=8.0 Hz, 1H), 7.89-7.75 (m, 4H), 4.85(s, 2H), 3.65-3.50 (m, 2H), 3.20-3.03 (m, 2H), 2.22-2.08 (m, 1H),2.10-1.96 (m, 1H), 1.88-1.65 (m, 4H), 1.54-1.38 (m, 1H), 1.38-1.17 (m,3H), 1.15-0.99 (m, 1H), 0.67 (t, J=7.5 Hz, 2H). ESI MS found forC₂₁H₃₀BN₃O₄ m/z [400.5 (M+1)].

Example 57-A: Preparation of2-amino-6-borono-2-(1-(2-(pyridin-3-yl)benzyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(2-(pyridin-3-yl)benzyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 2-(pyridin-3-yl)benzaldehyde is used as the aldehyde in step6. ¹H NMR (D₂O, 300 MHz) δ 8.82-8.75 (m, 2H), 8.56-8.50 (m, 1H),8.12-8.05 (m, 1H), 7.65-7.53 (m, 3H), 7.38-7.34 (m, 1H), 4.25 (s, 2H),3.44-3.35 (m, 2H), 2.68-2.51 (m, 2H), 1.96-1.80 (m, 2H), 1.70-1.52 (m,4H), 1.52-1.48 (m, 1H), 1.35-1.10 (m, 3H), 1.10-0.95 (m, 1H), 0.66 (t,J=7.5 Hz, 2H). ESI MS found for C₂₃H₃₂BN₃O₄ m/z [426.3 (M+1)].

Example 58-A: Preparation of2-amino-6-borono-2-(1-((3′-methoxybiphenyl-2-yl)methyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-((3′-methoxybiphenyl-2-yl)methyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 3′-methoxybiphenyl-2-carbaldehyde is used as the aldehyde instep 6. ¹H NMR (D₂O, 300 MHz) δ 7.52-7.28 (m, 5H), 7.00-6.83 (m, 3H),4.28 (s, 2H), 3.73 (s, 3H), 3.32-3.22 (m, 2H), 2.60-2.45 (m, 2H),1.90-1.75 (m, 2H), 1.70-1.50 (m, 4H), 1.38-1.10 (m, 4H), 1.10-0.94 (m,1H), 0.62 (t, J=7.5 Hz, 2H). ESI MS found for C₂₅H₃₅BN₂O₅ m/z [455.4(M+1)].

Example 59-A: Preparation of2-amino-6-borono-2-(1-(3,4-difluorophenethyl)piperidin-4-yl)hexanoicacid acid dihydrochloride

2-Amino-6-borono-2-(1-(3,4-difluorophenethyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 2-(3,4-difluorophenyl)acetaldehyde is used as the aldehydein step 6. ¹H NMR (D₂O, 300 MHz) δ 7.15-7.03 (m, 2H), 6.97-6.90 (m, 1H),3.63-3.51 (m, 2H), 3.28-3.15 (m, 2H), 2.99-2.80 (m, 4H), 2.10-1.97 (m,2H), 1.87-1.63 (m, 4H), 1.52-1.35 (m, 1H), 1.35-1.15 (m, 3H), 1.14-0.98(m, 1H), 0.65 (t, J=7.2 Hz, 2H). ESI MS found for C₁₉H₂₉BF₂N₂O₄ m/z[399.2 (M+1)].

Example 60-A: Preparation of2-amino-6-borono-2-(1-(chroman-8-ylmethyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(chroman-8-ylmethyl)piperidin-4-yl)hexanoic acidis prepared in a manner analogous to that set forth in Example 118,except that chroman-8-carbaldehyde is used as the aldehyde in step 6. ¹HNMR (D₂O, 300 MHz) δ 7.12 (d, J=8.2 Hz, 1H), 7.06 (d, J=8.2 Hz, 1H),6.80 (dd, J₁=8.2 Hz, J₂=8.2 Hz, 1H), 4.17-4.09 (m, 4H), 3.52-3.42 (m,2H), 3.00-2.86 (m, 2H), 2.71-2.64 (m, 2H), 2.09-1.95 (m, 2H), 1.91-1.64(m, 6H), 1.49-1.34 (m, 1H), 1.35-1.18 (m, 3H), 1.16-0.99 (m, 1H), 0.64(t, J=7.5 Hz, 2H). ESI MS found for C₂₁H₃₃BN₂O₅ m/z [405.3 (M+1)].

Example 61-A: Preparation of2-amino-6-borono-2-(1-(indolin-7-ylmethyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(indolin-7-ylmethyl)piperidin-4-yl)hexanoic acidis prepared in a manner analogous to that set forth in Example 118,except that indoline-7-carbaldehyde is used as the aldehyde in step 6.¹H NMR (D₂O, 300 MHz) δ 7.54-7.36 (m, 3H), 4.30 (s, 2H), 3.80 (t, J=7.8Hz, 2H), 3.60-3.45 (m, 2H), 3.25 (t, J=7.8 Hz, 2H), 3.11-2.95 (m, 2H),2.13-1.98 (m, 2H), 1.90-1.65 (m, 4H), 1.50-1.35 (m, 1H), 1.38-1.14 (m,3H), 1.16-0.99 (m, 1H), 0.66 (t, J=7.2 Hz, 2H). ESI MS found forC₂₀H₃₂BN₃O₄ m/z [390.3 (M+1)].

Example 62-A: Preparation of2-amino-6-borono-2-(1-((1,3-dimethyl-1H-pyrazol-5-yl)methyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-((1,3-dimethyl-1H-pyrazol-5-yl)methyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 1,3-dimethyl-1H-pyrazole-5-carbaldehyde is used as thealdehyde in step 6. ¹H NMR (D₂O, 300 MHz) δ 6.30 (s, 1H), 4.32 (s, 2H),3.73 (s, 3H), 3.58-3.47 (m, 2H), 3.07-2.94 (m, 2H), 2.12 (s, 3H),2.11-2.00 (m, 2H), 1.90-1.68 (m, 4H), 1.51-1.4 (m, 1H), 1.36-1.22 (m,3H), 1.18-1.04 (m, 1H), 0.66 (t, J=7.2 Hz, 2H). ESI MS found forC₁₇H₃₁BN₄O₄ m/z [367.4 (M+1)].

Example 63-A: Preparation of2-amino-6-borono-2-(1-(3-(4-(trifluoromethyl)phenyl)propyl)piperidin-4-yl)hexanoicacid acid dihydrochloride

2-Amino-6-borono-2-(1-(3-(4-(trifluoromethyl)phenyl)propyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 3-(4-(trifluoromethyl)phenyl)propanal is used as thealdehyde in step 6. ¹H NMR (D₂O, 300 MHz) δ 7.56 (d, J=8.6 Hz, 1H), 7.32(d, J=8.6 Hz, 1H), 3.60-3.47 (m, 2H), 3.03-2.92 (m, 2H), 2.92-2.75 (m,2H), 2.72-2.61 (m, 2H), 2.11-1.88 (m, 4H), 1.90-1.64 (m, 4H), 1.52-1.35(m, 1H), 1.35-1.15 (m, 3H), 1.16-0.99 (m, 1H), 0.65 (t, J=7.2 Hz, 2H).ESI MS found for C₂₁H₃₂BF₃N₂O₄ m/z [445.2 (M+1)].

Example 64-A: Preparation of2-amino-6-borono-2-(1-(4-(3,4-dichlorophenoxy)benzyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(4-(3,4-dichlorophenoxy)benzyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 4-(3,4-dichlorophenoxy)benzaldehyde is used as the aldehydein step 6. ¹H NMR (D₂O, 300 MHz) δ 7.44-7.36 (m, 2H), 7.20-7.03 (m, 4H),6.89 (dd, J₁=8.8 Hz, J₂=3.0 Hz, 1H), 4.14 (s, 2H), 3.54-3.48 (m, 2H),2.98-2.84 (m, 2H), 2.10-1.95 (m, 2H), 1.85-1.64 (m, 4H), 1.50-1.32 (m,1H), 1.35-1.18 (m, 3H), 1.16-1.01 (m, 1H), 0.66 (t, J=7.5 Hz, 2H). ESIMS found for C₂₄H₃₁BCl₂N₂O₅ m/z [509.3 (M+1), 511.3 (M+1)].

Example 65-A: Preparation of2-(1-(3-((1H-pyrazol-1-yl)methyl)benzyl)piperidin-4-yl)-2-amino-6-boronohexanoicacid dihydrochloride

2-(1-(3-((1H-pyrazol-1-yl)methyl)benzyl)piperidin-4-yl)-2-amino-6-boronohexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 3-((1H-pyrazol-1-yl)methyl)benzaldehyde is used as thealdehyde in step 6. ¹H NMR (D₂O, 300 MHz) δ 7.82 (d, J=2.6 Hz, 1H), δ7.66 (d, J=2.6 Hz, 1H), 7.41-7.18 (m, 4H), 6.41 (dd, J₁=2.6 Hz, J₂=2.6Hz, 1H), 5.39 (s, 2H), 4.15 (s, 2H), 3.50-3.38 (m, 2H), 2.97-2.82 (m,2H), 2.15-1.92 (m, 2H), 1.87-1.62 (m, 4H), 1.49-1.32 (m, 1H), 1.35-1.18(m, 3H), 1.16-0.99 (m, 1H), 0.64 (t, J=7.5 Hz, 2H). ESI MS found forC22H33BN4O4 C₂₂H₃₃BN₂O₄ m/z [429.3 (M+1)].

Example 66-A: Preparation of2-amino-6-borono-2-(1-(3-(2,4-dichlorophenyl)propyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(3-(2,4-dichlorophenyl)propyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example 118,except that 3-(2,4-dichlorophenyl)propanal is used as the aldehyde instep 6. ¹H NMR (D₂O, 500 MHz) δ 7.42 (s, 1H), 7.22 (bs, 2H), 3.65-3.55(m, 2H), 3.14-3.05 (m, 2H), 3.00-2.97 (m, 2H), 2.75-2.67 (m, 2H),2.29-2.19 (m, 1H), 2.17-2.08 (m, 1H), 2.02-1.79 (m, 6H), 1.62-1.50 (m,1H), 1.45-1.29 (m, 3H), 1.21-1.10 (m, 1H), 0.63 (t, J=7.2 Hz, 2H). ESIMS found for C₂₀H₃₁BCl₂N₂O₄ m/z [427.7 (M+1−18)].

Example 67-A: Preparation of2-amino-2-((R)-1-benzylpyrrolidin-3-yl)-6-boronohexanoic aciddihydrochloride

2-Amino-2-((R)-1-benzylpyrrolidin-3-yl)-6-boronohexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 118, except (R)-1-(tert-butoxycarbonyl)pyrrolidine-3-carboxylicacid is used as the carboxylic acid in step 1. ESI MS found forC₁₇H₂₇BN₂O₄ m/z [335.2 (M+1)].

Example 68-A: Preparation of2-amino-2-((S)-1-benzylpyrrolidin-3-yl)-6-boronohexanoic aciddihydrochloride

2-Amino-2-((S)-1-benzylpyrrolidin-3-yl)-6-boronohexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 118, except (S)-1-(tert-butoxycarbonyl)pyrrolidine-3-carboxylicacid is used as the carboxylic acid in step 1. ESI MS found forC₁₇H₂₇BN₂O₄ m/z [335.1 (M+1)].

Example 69-A: Preparation of2-amino-6-borono-2-((S)-1-(3,4-dichlorobenzyl)piperidin-3-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-((S)-1-(3,4-dichlorobenzyl)piperidin-3-yl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 118, except(S)-1-(tert-butoxycarbonyl)piperidine-3-carboxylic acid is used as thecarboxylic acid in step 1 and 3,4-dichlorobenzaldehyde is used as thealdehyde in step 6. ESI MS found for C₁₈H₂₇BCl₂N₂O₄ m/z [417.4 (M+1)].

Example 71-A: Preparation of(R)-2-amino-2-(1-benzylpiperidin-4-yl)-6-boronohexanoic acid

Step 1: 1-benzyl-N-methoxy-N-methylpiperidine-4-carboxamide

A solution of ethyl 1-benzylpiperidine-4-carboxylate (10.0 g, 40.4 mmol)and N,O-dimethylhydroxylamine hydrochloride (6.12 g, 62.6 mmol) in THF(80 mL) was cooled to 0° C. prior to the addition of i-PrMgCl (121.2mmol, 60.6 mL, 2 M in THF) dropwise. The reaction was stirred for 1 h,then quenched by addition of saturated aqueous ammonium chloride (90mL). The aqueous and organic layers were separated. The separatedaqueous phase was further extracted with ethyl acetate. The combinedorganic layers were washed with saturated aqueous sodium chloride, driedover MgSO₄, and concentrated in vacuo. The residue was chromatographedon silica gel (2-18% methanol in dichloromethane) to afford the desiredproduct (8.88 g, 84%). R_(f) 0.45 (10% MeOH/CH₂Cl₂). ¹H NMR (CDCl₃, 300MHz) δ 7.40-7.20 (m, 5H), 3.69 (s, 3H), 3.51 (s, 2H), 3.17 (s, 3H), 2.94(d, 2H, J=11.4 Hz), 2.63-2.66 (m, 1H), 2.01 (td, J=11.7, 2.9 Hz, 2H),1.83 (qd, J=12.8, 3.7 Hz, 2H), 1.72-1.67 (m, 2H). ESI MS found forC₁₅H₂₂N₂O₂ 112/Z [263.3 (M+1)].

Step 2: 1-(1-benzylpiperidin-4-yl)pent-4-en-1-one

A solution of 1-benzyl-N-methoxy-N-methylpiperidine-4-carboxamide (8.88g, 33.0 mmol) in THF (40 mL, 0.8 M) was cooled to 0° C. and treated witha 0.5 M solution of 3-butenylmagnesium bromide (51 mmol, 102 mL) in adropwise manner. After stirring for 4 h the reaction was quenched with 1N HCl (24 mL), neutralized with 5% aqueous sodium bicarbonate anddiluted with ethyl acetate. The layers were separated and the aqueousphase was extracted with ethyl acetate. The combined organic layers werewashed with saturated aqueous sodium chloride, dried over MgSO₄, andconcentrated in vacuo. The residue was chromatographed on silica (2-20%methanol in dichloromethane) to afford the desired product (4.95 g,57%). R_(f) 0.22 (10% MeOH/CH₂Cl₂). ¹H NMR (CDCl₃, 300 MHz) δ 7.38-7.21(m, 5H), 5.82-5.76 (m, 1H), 5.15-4.95 (m, 2H), 3.50 (s, 2H), 2.91 (d,J=11.2 Hz, 2H), 2.54 (t, J=7.3 Hz, 2H), 2.39-2.23 (m, 3H), 2.06-1.97 (m,2H), 1.82-1.61 (m, 4H). ESI MS found for C₁₇H₂₃NO m/z [258.2 (M+1)].

Step 3:(R,Z)—N-(1-(1-benzylpiperidin-4-yl)pent-4-enylidene)-2-methylpropane-2-sulfinamide

A solution of 1-(1-benzylpiperidin-4-yl)pent-4-en-1-one (6.11 g, 21.3mmol) and (R)-2-methylpropane-2-sulfinamide (3.62 g, 27.6 mmol) in THF(71 mL, 0.3 M) was treated with titanium (IV) ethoxide (12.6 g, 55.3mmol) and heated to 70° C. overnight. Because the reaction wasincomplete, additional portions of (R)-2-methylpropane-2-sulfinamide(1.81 g, 13.8 mmol) and titanium (IV) ethoxide (6.3 g, 27.7 mmol) wereadded and the mixture was heated to 75° C. for 6 more hours. Thereaction was quenched by pouring it slowly into rapidly stirredsaturated aqueous sodium chloride (100 mL) and filtering through Celite.The Celite pad was washed with ethyl acetate (3×) and the combinedorganics were washed with saturated aqueous sodium chloride, dried overMgSO₄, and concentrated in vacuo. The residue was chromatographed onsilica gel (60% ethyl acetate in heptane) to afford the desired product(3.24 g, 42%). R_(f) 0.44 (EtOAc). ¹H NMR (CDCl₃, 300 MHz) δ 7.34-7.19(m, 5H), 5.88-5.75 (m, 1H), 5.09-4.94 (m, 2H), 3.50 (d, J=5.5 Hz, 2H),2.97-2.83 (m, 2H), 2.74-2.70 (m, 1H), 2.55-2.23 (m, 4H), 2.00 (t, J=8.8Hz, 2H), 1.77-1.63 (m, 4H), 1.23 (s, 9H). ESI MS found for C₂₁H₃₂N₂OSm/z [361.4 (M+1)].

Step 4:(R)—N—((R)-1-(1-benzylpiperidin-4-yl)-1-cyanopent-4-enyl)-2-methylpropane-2-sulfinamide

A solution of(R,Z)—N-(1-(1-benzylpiperidin-4-yl)pent-4-enylidene)-2-methylpropane-2-sulfinamide(2.74 g, 7.6 mmol) in THF (130 mL, 0.06 M) was cooled to −78° C.Separately, a 1 M solution of Et₂AlCN (11.4 mmol, 11.4 mL) was dissolvedin THF (20 mL) and cooled to −78° C. iPrOH (0.64 mL, 8.26 mmol) wasadded dropwise and the solution was warmed to RT over 20 min, then addeddropwise to the sulfinamide solution. The reaction was allowed to warmgradually to RT and stirred overnight. The reaction was quenched withsaturated aqueous ammonium chloride (50 mL) and filtered through Celite.The Celite pad was washed with ethyl acetate (3×) and the combinedorganics were washed saturated aqueous sodium chloride, dried overMgSO₄, and concentrated in vacuo. The residue was chromatographed onsilica gel (1-9% methanol in dichloromethane and again with 2-5%methanol in ethyl acetate) to afford the desired product (1.99 g, 67%)along with its undesired diastereoisomer (0.46 g, 15%). R_(f) 0.26 (10%MeOH/CH₂Cl₂). ¹H NMR (CDCl₃, 300 MHz) δ 7.31-7.25 (m, 5H), 5.83-5.78 (m,1H), 5.13-5.03 (m, 2H), 3.51 (d, J=1.5 Hz, 2H), 3.41 (s, 1H), 3.00 (d,J=11.0 Hz, 2H), 2.34-2.29 (m, 2H), 2.05-1.83 (m, 6H), 1.60-1.44 (m, 3H),1.25 (s, 9H). ESI MS found for C₂₂H₃₃N₃OS m/z [388.4 (M+1)].

Step 5:(R)—N—((R)-1-(1-benzylpiperidin-4-yl)-1-cyano-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pentyl)-2-methylpropane-2-sulfinamide

A solution of(R)—N—((R)-1-(1-benzylpiperidin-4-yl)-1-cyanopent-4-enyl)-2-methylpropane-2-sulfinamide(364 mg, 0.94 mmol), [Ir(COD)Cl]₂ (31 mg, 0.047 mmol) and dppe (37 mg,0.094 mmol) in dichloromethane (9.4 mL) was stirred for 20 min thentreated with pinacolborane (180 mg, 1.41 mmol). After stirring overnightat room temperature, the reaction was diluted with ethyl acetate, washedwith saturated aqueous sodium chloride, dried over MgSO₄, andconcentrated. The resulting residue was purified by flash columnchromatography (silica gel, eluting with 1-10% methanol indichloromethane) to afford the desired product (170 mg, 35%). R_(f) 0.43(10% MeOH/CH₂Cl₂). ¹H NMR (CDCl₃, 300 MHz) δ 7.34-7.24 (m, 5H), 3.50 (s,2H), 3.34 (s, 1H), 2.98 (d, J=11.4 Hz, 2H), 2.03-1.94 (m, 2H), 1.87-1.71(m, 3H), 1.60-1.40 (m, 8H), 1.26 (s, 9H), 1.24 (s, 12H), 0.81 (t, J=7.3Hz, 2H). ESI MS found for C₂₈H₄₆BN₃O₃S m/z [515.9 (M+1)].

Step 6: (R)-2-amino-2-(1-benzylpiperidin-4-yl)-6-boronohexanoic acid

(R)—N—((R)-1-(1-benzylpiperidin-4-yl)-1-cyano-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pentyl)-2-methylpropane-2-sulfinamide(170 mg, 0.33 mmol) was treated with 6 N HCl (3.3 mL) and heated to 105°C. After stirring overnight, the reaction was diluted with water, washeddichloromethane, and concentrated. The resulting residue was azeotropedwith toluene, dried under high vacuum and purified by HPLC (10-100%acetonitrile/H₂O) to yield the desired product (39 mg, 34%). ¹H NMR(CD₃OD, 300 MHz) δ 7.56-7.43 (m, 5H), 4.29 (s, 2H), 3.47 (br, 2H), 3.06(br, 2H), 2.76 (br, 1H), 2.54 (t, J=7.0 Hz, 2H), 2.11 (d, J=13.9 Hz,2H), 1.77 (br, 2H), 1.59-1.44 (m, 2H), 1.40-1.29 (m, 2H), 0.78 (t, J=8.1Hz, 2H). ESI MS found for C₁₈H₂₉BN₂O₄ m/z [331.2 (M+1)-H₂O].

Example 72-A: Preparation of 2-amino-2-(azepan-4-yl)-6-boronohexanoicacid dihydrochloride

2-Amino-2-(azepan-4-yl)-6-boronohexanoic acid dihydrochloride isprepared in a manner analogous to that set forth in Example 118, except1-(benzyloxycarbonyl)azepane-4-carboxylic acid was used as the acid instep 1 and Steps 5 and 6 were omitted. ¹H NMR (D₂O, 300 MHz) δ 3.39-3.26(m, 1H), 3.26-3.15 (m, 1H), 3.12-2.97 (m, 2H), 2.20-1.40 (m, 9H),1.35-1.13 (m, 3H), 1.13-0.99 (m, 1H), 0.65 (t, J=7.2 Hz, 2H). ESI MSfound for C₁₂H₂₅BN₂O₄ m/z [272.2 (M+1), 255.0 (M+1−18)].

Example 73-A: Preparation of2-amino-6-borono-2-(1-(3,4-dichlorobenzyl)azepan-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(3,4-dichlorobenzyl)azepan-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 118, except 1-(benzyloxycarbonyl)azepane-4-carboxylic acid wasused as the acid in step 1 and 3,4-dichlorobenzaldehyde was used as thealdehyde in Step 6. ¹H NMR (D₂O, 300 MHz) δ 7.54 (bs, 1H), 7.48 (d,J=7.8 Hz, 1H), 7.26 (bd, J=7.8 Hz, 1H), 4.20 (bs, 2H), 3.52-2.90 (m,4H), 2.31-2.10 (m, 1H), 2.11-1.44 (m, 8H), 1.35-1.14 (m, 3H), 1.16-0.98(m, 1H), 0.64 (t, J=7.5 Hz, 2H). ESI MS found for C₁₉H₂₉BCl₂N₂O₄ m/z[431.2&433.2 (M+1), 413.1&315.1 (M+1-18)].

Example 74-A: Preparation ofcis-2-amino-2-(3-(benzylamino)cyclobutyl)-6-boronohexanoic aciddihydrochloride

Step 1: Synthesis of3-(benzyl(tert-butoxycarbonyl)amino)cyclobutanecarboxylic acid

A solution of 3-oxo-1 cyclobutane carboxylic acid (4 g, 35 mmol, 1 eq),benzyl amine (19 ml, 175 mmol, 5 eq), and acetic acid (2.1 mL, 35 mmol,1 eq) in 1,2-dichloroethane was stirred at room temperature for 1 h.Sodium triacetoxyborohydride (11.1 g, 52.5 mmol, 1.5 eq) was added andstirring was continued for 2 days, the solution was basified to pH 13with aq NaOH (1 N) and washed with dichloromethane. The aqueous layerwas charged with di-tert-butyl dicarbonate (45 g, 210 mmol, 6 eq) andstirred overnight. After acidifying to pH 5, the reaction mixture wasextracted with ethyl acetate, washed with sat'd aq sodium chloride,dried over MgSO₄, filtered and concentrated. Purification by flashchromatography (1-20% methanol in dichloromethane) gave3-(benzyl(tert-butoxycarbonyl)amino)cyclobutanecarboxylic acid as awhite solid (7.96 g, 24.3 mmol, 69%). ESI MS found for C₁₇H₂₃BNO₄ m/z[304 (M−1)].

Step 2: Synthesis of tert-butylbenzyl(3-(methoxy(methyl)carbamoyl)cyclobutyl)carbamate

A solution of 3-(benzyl)tert-butoxycarbonyl)amino)cyclobutanecarboxylicacid (4.96 g, 15.2 mmol) in dichloromethane (80 mL, 0.19 M) was treatedwith EDC (5.8 g, 30.3 mmol, 2 eq), N,O-dimethylhydroxylaminehydrochloride (3.0 g, 30.3 mmol, 2 eq), and triethyl amine (8.5 mL, 60.7mmol, 4 eq) and stirred for 16 h. The resulting solution was washedsuccessively with water, 1 M HCl, sat'd aq sodium chloride, dried overanhydrous MgSO₄, filtered and concentrated. Purification by flashchromatography (1-20% methanol in dichloromethane) gave tert-butylbenzyl(3-(methoxy(methyl)carbamoyl)cyclobutyl) carbamate as an off-whitesolid (4.04 g, 72%). ¹H NMR (CD₃OD, 300 MHz) δ 7.40-7.16 (m, 5H),4.60-4.20 (m, 1H), 4.52 (brs, 2H), 3.77 (s, 3H), 3.22-3.00 (brs, 4H),2.60-2.20 (m, 4H), 1.58-1.08 (brs, 9H), LCMS, C₁₉H₂₈N₂O₄ m/z [349 (M+1),371.3 (M+23)].

Step 3: Synthesis of tert-butylbenzyl(3-pent-4-enoylcyclobutyl)carbamate

While under a nitrogen atmosphere, a solution of tert-butylbenzyl(3-(methoxy(methyl)carbamoyl)cyclobutyl)carbamate (8.68 g, 23.5mmol, 1 eq), in tetrahydrofuran (100 mL) was cooled to 0° C. and treatedwith 4-butenylmagnesiun bromide (0.5 M in THF, 70.4 mL, 35.2 mmol, 1.5eq) dropwise. After stirring for 0.5 hour at 0° C., the reaction mixturewas warmed to room temperature for an additional 3 h. Once complete, thereaction mixture was poured into water, acidified to pH 3-4 with 1 Nhydrochloric acid and extracted with ethyl acetate (3×). The combinedorganic layers was washed with saturated aqueous sodium chloride, driedover anhydrous magnesium sulfate, filtered and concentrated.Purification by flash column chromatography (silica gel, 0-40% ethylacetate in heptane) gave tert-butylbenzyl(3-pent-4-enoylcyclobutyl)carbamate as a colorless oil (7.7 g,21.1 mmol, 90%). ¹H NMR (CDCl₃, 300 MHz) δ 7.33-7.11 (m, 5H), 5.84-5.67(m, 1H), 5.04-4.92 (m, 2H), 4.45 (brs, 3H), 2.89-2.70 (m, 1H), 2.48-2.15(m, 8H), 1.5-1.08 (brs, 9H), ESI MS found for C₂₁H₂₉NO₃ m/z [366.2(M+23)].

Step 4: Synthesis of tert-butyl3-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)cyclobutyl(benzyl)carbamate

A solution of tert-butyl benzyl(3-pent-4-enoylcyclobutyl)carbamate (7.7g, 21.1 mmol, 5 eq), t-butyl isonitrile (12 mL, 106 mmol, 10 eq) andammonium acetate (16.3 g, 212 mmol) in 2,2,2-trifluoroethanol (24 mL,0.9 M) was stirred at room temperature for 3 days. The reaction mixturewas diluted with ethyl acetate, quenched with 2 M HCl and extracted withethyl acetate. The organic layer was washed successively with 2 M HCland sat'd aq sodium chloride, dried over MgSO₄, filtered andconcentrated. Purification by column chromatography (ethyl acetate inhexanes) gave cis-tert-butyl3-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)cyclobutyl(benzyl)carbamateas a yellow solid (8.9 g, 17.5 mmol, 83%). ¹H NMR (CDCl₃, 300 MHz) δ7.32-7.10 (m, 6H), 6.08 (brs, 1H), 5.80-5.64 (m, 1H), 5.01-4.87 (m, 2H),4.42 (brs, 2H), 4.41-4.08 (m, 1H), 2.79-2.58 (m, 1H), 2.40-1.99 (m, 8H),1.98-1.80 (m, 3H), 1.56-1.08 (m, 18H), ESI MS found for C₂₈H₄₃N₃O₄ m/z[508.2 (M+23)] and trans-tert-butyl3-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)cyclobutyl(benzyl)carbamateas a white foam (1.1 g, 2.2 mmol, 10%). ¹H NMR (CDCl₃, 300 MHz) δ7.32-7.11 (m, 5H), 6.79 (brs, 1H), 5.83-5.68 (m, 1H), 5.56 (brs, 1H),5.02-4.88 (m, 2H), 4.54-4.37 (m, 2H), 4.35-4.16 (m, 1H), 2.94-2.75 (m,2H), 2.51-2.39 (m, 1H), 2.38-2.19 (m, 2H), 2.18-1.90 (m, 5H), 1.86-1.70(m, 1H), 1.67-1.58 (m, 1H), 1.47-1.22 (m, 18H), ESI MS found forC₂₈H₄₃N₃O₄ m/z [486.5 (M+1), 508.0 (M+23)].

Step 5: Synthesis of cis-tert-butyl3-(2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)cyclobutyl(benzyl)carbamate

After stirring for 30 min, a solution of cis-tert-butyl3-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)cyclobutyl(benzyl)carbamate(5.34 g, 10.5 mmol), chloro-1,5-cyclooctadiene iridium(I) dimer (212 mg,0.32 mmol, 3 mol %) and 1,2-bis(diphenylphosphino)ethane (252 mg, 0.63mmol, 6 mol %) in dichloromethane (50 mL) was cooled to 0° C. andcarefully treated with 4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (3.1 mL,21.1 mmol, 2 eq) over 5 min. After slowly warming to room temperatureand stirring overnight, the reaction was poured into water and extractedwith ethyl acetate (3×). The combined organic phase was washed withsaturated aqueous sodium chloride, dried over anhydrous magnesiumsulfate, filtered and concentrated. Purification by flash columnchromatography (silica gel, 10-40% ethyl acetate in heptane) gavecis-tert-butyl3-(2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)cyclobutyl(benzyl)carbamate(4.8 g, 7.83 mmol, 74%). ESI MS found for C₃₄H₅₆BN₃O₆ m/z [614.2 (M+1),636.2 (M+23)].

Step 6: cis-2-amino-2-(3-(benzylamino)cyclobutyl)-6-boronohexanoic aciddihydrochloride

A solution of cis-tert-butyl3-(2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)cyclobutyl(benzyl)carbamate(200 mg, 0.33 mmol) in 6 N HCl was heated to reflux for 16 h, cooled toroom temperature and concentrated to dryness. Purification bypreparative HPLC (20% acetonitrile in water with 0.1% trifluoroaceticacid) followed by treatment with aq HCl and evaporation gavecis-2-amino-6-borono-2-(3-benzylamino-cyclobutyl)-hexanoic aciddihydrochloride as a white solid (73.6 mg, 0.23 mmol, 70%). ¹H NMR (D₂O)δ 7.42-7.29 (m, 5H), 4.03 (s, 2H), 3.63-3.50 (m, 1H), 2.58-2.43 (m, 1H),2.43-2.12 (m, 3H), 1.97-1.72 (m, 2H), 1.68-1.52 (m, 1H), 1.36-0.96 (m,4H), 0.65 (t, J=7.5 Hz, 2H). MS found for C₁₇H₂₇BN₂O₄ m/z[317(M−18+¹)].

Example 75-A: Preparation oftrans-2-amino-2-(3-(benzylamino)cyclobutyl)-6-boronohexanoic aciddihydrochloride

Trans-2-amino-2-(3-(benzylamino)cyclobutyl)-6-boronohexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 74-A, except trans-tert-butyl3-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)cyclobutyl(benzyl)carbamateis used as the alkene in step 4. ¹H NMR (D₂O) δ 7.42-7.27 (m, 5H), 4.02(s, 2H), 3.72-3.57 (m, 1H), 3.01-2.84 (m, 1H), 2.64-2.48 (m, 1H),2.40-2.20 (m, 3H), 1.93-1.76 (m, 1H), 1.68-1.55 (m, 1H), 1.35-0.96 (m,4H), 0.64 (t, J=7.5 Hz, 2H). MS found for C₁₇H₂₇BN₂O₄ m/z[317(M−18+1)].

Example 76-A: Preparation ofcis-2-amino-6-borono-2-(3-(4-(trifluoromethoxy)benzylamino)cyclobutyl)hexanoicacid dihydrochloride

Cis-2-amino-6-borono-2-(3-(4-(trifluoromethoxy)benzylamino)cyclobutyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 74-A, except 4′-trifluoromethoxybenzylamine is used as theamine in step 1. ¹H NMR (CD₃OD) δ 7.66 (dt, J=8.7, 2.4 Hz, 2H), 7.37(dd, J=8.7, 0.9 Hz, 2H), 4.18 (s, 2H), 3.81-3.67 (m, 1H), 2.75-2.58 (m,1H), 2.57-2.34 (m, 3H), 2.33-2.19 (m, 1H), 2.06-1.90 (m, 1H), 1.86-1.72(m, 1H), 1.54-1.36 (m, 3H), 1.34-1.13 (m, 1H), 0.83 (t, J=7.4 Hz, 2H).MS found for C₁₈H₂₆BF₃N₂O₅ m/z[419(M+1)].

Example 77-A: Preparation ofcis-2-amino-2-(3-(biphenyl-4-ylmethylamino)cyclobutyl)-6-boronohexanoicacid dihydrochloride

Cis-2-amino-2-(3-(biphenyl-4-ylmethylamino)cyclobutyl)-6-boronohexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 74-A, except biphenyl-4-ylmethanamine is used as the amine instep 1. ¹H NMR (CD₃OD) δ 7.75-7.69 (m, 2H), 7.67-7.57 (m, 4H), 7.49-7.42(m, 2H), 7.41-7.13 (m, 1H), 4.19 (s, 2H), 3.82-3.65 (m, 1H), 2.75-2.60(m, 1H), 2.58-2.34 (m, 3H), 2.32-2.18 (m, 1H), 2.06-1.92 (m, 1H),1.86-1.72 (m, 1H), 1.54-1.36 (m, 3H), 1.32-1.15 (m, 1H), 0.83 (t, J=7.5Hz, 2H). MS found for C₂₃H₃₁BN₂O₄ m/z[411 (M+1)].

Example 78-A: Preparation ofcis-2-amino-6-borono-2-(3-((6-chlorobenzo[d][1,3]dioxol-5-yl)methylamino)cyclobutyl)hexanoicacid dihydrochloride

Cis-2-amino-6-borono-2-(3-((6-chlorobenzo[d][1,3]dioxol-5-yl)methylamino)cyclobutyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 74-A, except (6-chlorobenzo[d][1,3]dioxol-5-yl)methanamine isused as the amine in step 1. ¹H NMR (CD₃OD) δ 7.13 (s, 1H), 7.03 (s,1H), 6.06 (s, 2H), 4.20 (s, 2H), 3.82-3.70 (m, 1H), 2.76-2.61 (m, 1H),2.60-2.36 (m, 3H), 2.32-2.18 (m, 1H), 2.06-1.90 (m, 1H), 1.88-1.72 (m,1H), 1.54-1.34 (m, 3H), 1.32-1.14 (m, 1H), 0.83 (t, J=7.2 Hz, 2H). MSfound for C₁₈H₂₆BClN₂O₆ m/z[413.0 (M+1)].

Example 79-A: Preparation ofcis-2-amino-6-borono-2-(3-(quinolin-8-ylmethylamino)cyclobutyl)hexanoicacid dihydrochloride

Cis-2-amino-6-borono-2-(3-(quinolin-8-ylmethylamino)cyclobutyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 74-A, except quinolin-8-ylmethanamine is used as the amine instep 1. ¹H NMR (CD₃OD) δ 9.20 (dd, J=5.1, 1.5 Hz, 1H), 9.00 (dd, J=8.7,1.5 Hz, 1H), 8.33 (dd, J=8.4, 1.2 Hz, 1H), 8.29 (dd, J=7.2, 1.2 Hz, 1H),8.01 (dd, J=8.4, 5.1 Hz, 1H), 7.92 (dd, J=8.4, 7.2 Hz, 1H), 4.84 (s,2H), 4.08-3.92 (m, 1H), 2.80-2.32 (m, 5H), 2.08-1.92 (m, 1H), 1.89-1.74(m, 1H), 1.54-1.36 (m, 3H), 1.34-1.15 (m, 1H), 0.83 (t, J=7.5 Hz, 2H).MS found for C₂₀H₂₈BN₃O₄ m/z[386(M+1)].

Example 80-A: Preparation ofcis-2-amino-6-borono-2-(3-(naphthalen-1-ylmethylamino)cyclobutyl)hexanoicacid dihydrochloride

Cis-2-amino-6-borono-2-(3-(naphthalen-1-ylmethylamino)cyclobutyl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 74-A, except naphthalen-1-ylmethanamine is used as the aminein step 1. ¹H NMR (CD₃OD) δ 8.20-8.14 (m, 1H), 8.03-7.96 (m, 2H),7.76-7.66 (m, 2H), 7.64-7.53 (m, 2H), 4.66 (s, 2H), 3.96-3.77 (m, 1H),2.76-2.62 (m, 1H), 2.60-2.36 (m, 0.3H), 2.35-2.21 (m, 1H), 2.05-1.89 (m,1H), 1.88-1.72 (m, 1H), 1.53-1.35 (m, 3H), 1.34-1.13 (m, 1H), 0.82 (t,J=7.5 Hz, 2H). MS found for C₂₁H₂₉BN₂O₄ m/z[385 (M+1)].

Example 81-A: Preparation ofcis-2-amino-2-(3-aminocyclobutyl)-6-boronohexanoic acid dihydrochloride

2-Amino-2-(3-aminocyclobutyl)-6-boronohexanoic acid dihydrochloride isprepared in a manner analogous to that set forth in Example 118, except(1s,3s)-3-(tert-butoxycarbonylamino)cyclobutane carboxylic acid was usedas the acid in step 1 and Steps 5 and 6 were omitted. ¹H NMR (D₂O, 300MHz) δ 3.62-3.52 (m, 1H), 2.58-2.31 (m, 3H), 2.21 (q, J=10.3 Hz, 1H),1.92-1.78 (m, 2H), 1.65-1.55 (m, 1H), 1.36-1.20 (m, 3H), 1.18-1.01 (m,1H), 0.66 (t, J=7.7 Hz, 2H). ESI MS found for C₁₀H₂₁B₁N₂O₄ m/z [245.1(M+1)].

Example 82-A: Preparation ofcis-2-amino-6-borono-2-(3-(4-chlorobenzylamino)cyclobutyl)hexanoic aciddihydrochloride

Cis-2-amino-6-borono-2-(3-(4-chlorobenzylamino)cyclobutyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 118, except (1s,3s)-3-(tert-butoxycarbonylamino)cyclobutanecarboxylic acid was used as the acid in step 1 and 4-chlorobenzaldehydeis used as the aldehyde in Step 6. ¹H NMR (D₂O, 300 MHz) δ 7.38 (d,J=8.4 Hz, 2H), 7.30 (d, J=8.4 Hz, 2H), 4.02 (s, 3H), 3.61-3.53 (m, 1H),2.45-2.20 (m, 4H), 1.94-1.69 (m, 2H), 1.56-1.45 (m, 1H), 1.32-1.03 (m,4H), 0.66 (t, J=7.7 Hz, 2H). ESI MS found for C₁₇H₂₆B₁Cl₁N₂O₄ m/z [369.3(M+1)].

Example 83-A: Preparation ofcis-2-amino-6-borono-2-(3-(isobutylamino)cyclobutyl)hexanoic aciddihydrochloride

Cis-2-amino-6-borono-2-(3-(isobutylamino)cyclobutyl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 118, except (1s,3s)-3-(tert-butoxycarbonylamino)cyclobutanecarboxylic acid was used as the acid in step 1 and isobutyraldehyde isused as the aldehyde in Step 6. ESI MS found for C₁₄H₂₉B₁N₂O₄ m/z [301.1(M+1)].

Example 84-A: Preparation ofcis-2-Amino-6-borono-2-[4-(4-Chlorobenzoyl)-cyclohexyl]hexanoic acidhydrochloride Step 1: cis-4-(4-Chlorobenzoyl)-cyclohexanecarboxylicacid, methoxy-methyl amide

EDC (2.87 g, 15.0 mmol) was added portionwise to a stirred solution ofcis-4-(4-chlorobenzoyl)-cyclohexanecarboxylic acid (2.0 g, 7.5 mmol),DMAP (5 mg), HOBt (5 mg) and N,O-dimethylhydroxylamine hydrochloride(1.46 g, 15 mmol) in dichloromethane (40 mL). Triethylamine (2.28 g,3.14 mL, 22.5 mmol) was added dropwise, and the reaction mixture wasstirred at room temperature overnight. The resulting solution was pouredinto water, and extracted with ethyl acetate (3×). The combined organicphase was washed with saturated aqueous sodium chloride, dried overanhydrous magnesium sulfate, filtered and concentrated in vacuo to givecis-4-(4-chlorobenzoyl)-cyclohexanecarboxylic acid, methoxy-methyl amideas a colorless oil (1.6 g. 69%); ¹H NMR (CDCl₃, 300 MHz) δ 7.82 (d,J=8.5 Hz, 2H,), 7.41 (d, J=8.5 Hz, 2H), 3.69 (s, 3H), 3.35 (quin, J=5Hz, 1H), 3.16 (s, 3H), 2.80 (sept, J=4 Hz, 1H), 2.15 (m, 2H), 1.89 (m,2H), 1.72 (m, 4H).

Step 2:cis-4-[2-(4-Chlorophenyl)[1,3]-dioxolan-2-yl]-cyclohexanecarboxylicacid, methoxy-methyl amide

A solution of cis-4-(4-chlorobenzoyl)-cyclohexanecarboxylic acid,methoxy-methyl amide (1.6 g, 5.17 mmol), triethylorthoformate (843 mg,0.95 mL, 5.7 mmol), ethylene glycol (1.6 g, 1.45 mL, 25.9 mmol) andtoluenesulfonic acid monohydrate (50 mg) in toluene (50 mL) was stirredovernight at 60° C., and then cooled to room temperature andconcentrated to dryness in vacuo. The reaction mixture was redissolvedin ethyl acetate, washed with saturated aqueous sodium chloride, driedover anhydrous magnesium sulfate, filtered and concentrated in vacuo.Purification by flash column chromatography (silica gel, 0-30% ethylacetate in heptane) gavecis-4-[2-(4-chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexanecarboxylicacid, methoxy-methyl amide as a colorless oil (1.36 g, 74%); ¹H NMR(CDCl₃, 300 MHz) δ 7.33 (d, J=8.5 Hz,), 7.27 (d, J=8.5 Hz, 2H), 3.96 (m,2H), 3.68 (m, 2H), 3.64 (s, 3H), 3.14 (s, 3H), 2.83 (m, 1H), 1.96 (m,2H), 1.76 (m, 1H), 1.67 (m, 3H) and 1.47 (m, 4H); MS (+CI): m/z forC₁₈H₂₄ClNO₄: expected 353.1. found 354.2 (M+H)⁺.

Step 3:cis-1-{4-[2-(4-Chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexyl}pent-4-en-1-one

While under a nitrogen atmosphere, a solution ofcis-4-[2-(4-chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexanecarboxylicacid, methoxy-methyl amide (1.36 g, 3.85 mmol), in tetrahydrofuran (10mL) was cooled to 0° C. and treated with 4-butenylmagnesiun bromide (0.5M in THF, 19.24 mL, 9.62 mmol) in a dropwise manner. The solution wasstirred for 1 hour at 0° C. then allowed to warm to room temperatureovernight. The resulting solution was poured into water, acidified to pH3-4 with 1 N hydrochloric acid, and extracted with ethyl acetate (3×).The combined organic phase was washed with saturated aqueous sodiumchloride, dried over anhydrous magnesium sulfate, filtered andconcentrated in vacuo. Purification by flash column chromatography(silica gel, 0-25% ethyl acetate in heptane) gavecis-1-{4-[2-(4-chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexyl}pent-4-en-1-oneas a colorless oil (1.13 g, 84%); ¹H NMR (CDCl₃, 300 MHz) δ 7.31 (d,J=7.5 Hz, 2H), 7.27 (d, J=7.5 Hz, 2H), 5.78 (m, 1H), 4.96 (m, 2H), 3.94(m, 2H), 3.68 (m, 2H), 2.50 (m, 3H), 2.30 (m, 2H), 2.15 (dd, J=13, 3 Hz,2H), 1.76 (tt, J=11, 3 Hz, 1H), 1.36-1.56 (m, 4H) and 1.25 (td, J=13, 3Hz, 2H); MS (+CI): m/z for C₂₀H₂₅ClO₃: expected 348.2. found 349.2(M+H)⁺.

Step 4:cis-2-Acetylamino-2-{4-[2-(4-Chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexyl}hex-5-enoicacid, tert-butylamide

tert-Butyl isocyanide (404 mg, 0.55 mL, 4.86 mmol) was added to astirred slurry ofcis-1-{4-[2-(4-chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexyl}pent-4-en-1-one(1.13 g, 3.24 mmol) and ammonium acetate (999 mg, 12.96 mmol) in2,2,2-trifluoroethanol (0.5 mL), and the resultant slurry was stirred atroom temperature. After 8 days the reaction was poured into water andextracted with ethyl acetate (3×). The combined organic phase was washedwith saturated aqueous sodium chloride, dried over anhydrous magnesiumsulfate, filtered and concentrated in vacuo. Purification by flashcolumn chromatography (silica gel, 10-50% ethyl acetate in heptane) gavecis-2-acetylamino-2-{4-[2-(4-chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexyl}hex-5-enoicacid, tert-butylamide as a colorless oil (1.16 g, 71%); ¹H NMR (CDCl₃,300 MHz) δ 7.29 (m, 4H), 6.96 (br s, 1H NH), 5.76 (m, 1H), 5.44 (br s,NH, 1H), 4.94 (m, 2H), 3.94 (m, 2H), 3.68 (m, 2H), 2.93 (ddd, J₁=16.5hz, J₂=11.5 Hz, J₃=5.0 Hz, 1H), 1.90-2.08 (m, 2H), 1.96 (s, 3H),1.60-1.86 (m, (6H), 1.42 (m, 1H), 1.34 (s, 9H), 1.06 (m, 3H) and 0.86(m, 1H).

Step 5:cis-2-Acetylamino-2-{4-[2-(4-Chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexyl}-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaboron-2-yl)-hex-5-enoicacid, tert-butylamide

A solution ofcis-2-acetylamino-2-{4-[2-(4-Chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexyl}-hex-5-enoicacid, tert-butylamide (1.13 g, 2.3 mmol) in dichloromethane (10 mL), wastreated with chloro-1,5-cyclooctadiene iridium(I) dimer (46 mg, 3 mol %)and 1,2-bis(diphenylphosphino)ethane (55 mg, 6 mol %). The solution wasstirred at room temperature for 30 minutes and then4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (588 mg, 0.67 mL, 4.6 mmol) wasadded dropwise, and the reaction was then stirred overnight at roomtemperature. The reaction was poured into water and extracted with ethylacetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated in vacuo. Purification by flash columnchromatography (silica gel, 10-40% ethyl acetate in heptane) gavecis-2-acetylamino-2-{4-[2-(4-chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexyl}-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaboron-2-yl)-hex-5-enoicacid, tert-butylamide as a colorless oil (970 mg, 68%); ¹H NMR (CDCl₃,300 MHz) δ 7.28 (m, 4H), 6.92 (br s, NH, 1H), 5.41 (br s, NH, 1H), 3.94(m, 2H), 3.67 (m, 2H), 2.76 (m, 1H), 1.90-2.08 (m, 2H), 1.94 (s, 3H),1.60-1.86 (m, 4H), 1.18-1.42 (m, 5H), 1.32 (s, 9H), 1.23 (s, 12H),0.90-1.10 (m, 4H) and 0.72 (t, J=7.5 Hz, 2H); MS (+CI): m/z forC₃₃H₅₂BClN₂O₆: expected 618.4. found 619.3 (M+H)⁺, 641.4 (M+Na)⁺.

Step 6:(R)-2-amino-6-borono-2-((1s,4S)-4-(4-chlorobenzoyl)cyclohexyl)hexanoicacid

A solution ofcis-2-acetylamino-2-{4-[2-(4-chlorophenyl)-[1,3]-dioxolan-2-yl]-cyclohexyl}-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaboron-2-yl)-hex-5-enoicacid, tert-butylamide (970 mg) in 6 N HCl (15 mL) was stirred at 90° C.for 1 day. After cooling to room temperature, the reaction mixture wastransferred to a separatory funnel, diluted with deionized water (10 mL)and washed with dichloromethane (3×). The aqueous layer was frozen inliquid nitrogen and lyophilized to give title compound (545 mg, 88%). ¹HNMR (D₂O, 300 MHz) δ 7.77 (d, J=7.0 Hz, 2H), 7.38 (dd, J=7.0 Hz, 2H),3.24 (m, 1H), 1.76 (m, 6H), 1.54 (m, 1H), 1.24 (m, 6H), 1.06 (m, 2H) and0.64 (t, J=6.5 Hz, 2H); MS (+CI): m/z for C₁₉H₂₇BClNO₅: expected 395.2.found 396.2 (M+H)⁺, 378.2 (M+H−H₂O)⁺.

Example 85-A: Preparation of2-amino-6-borono-2-(1-(5-chloropyridin-2-yl)piperidin-4-yl)hexanoic acidhydrochloride Step 1:5′-Chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-carboxylic acid,methoxy-methyl-amide

EDC (1.61 g, 8.4 mmol) was added portionwise to a stirred solution of5′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-carboxylic acidhydrochloride (1.16 g, 4.19 mmol), DMAP (5 mg), HOBt (5 mg) andN,O-dimethylhydroxylamine hydrochloride (818 mg, 8.4 mmol) indichloromethane (20 mL). Triethylamine (1.69 g, 2.33 mL, 16.8 mmol) wasadded dropwise, and the reaction mixture was stirred at room temperatureovernight. The resulting solution was poured into water and extractedwith ethyl acetate (3×). The combined organic phase was washed withsaturated aqueous sodium chloride, dried over anhydrous magnesiumsulfate, filtered and concentrated in vacuo to give5′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-carboxylic acid,methoxy-methyl-amide as a white solid (1.05 g. 86%); ¹H NMR (CDCl₃, 300MHz) δ 8.05 (d, J=2.5 Hz, 1H), 7.36 (dd, J₁=9.0 Hz, J₂=2.5 Hz, 1H), 6.57(d, J=9.0 Hz, 1H), 4.25 (dt, J₁=13.0 Hz, J₂=3.0 Hz, 1H), 3.69 (s, 3H),3.16 (s, 3H), 2.88 (m, 3H), and 1.78 (m, 4H); MS (+CI): m/z forC₁₃H₁₈ClN₃O₂: expected 283.1. found 284.2 (M+H)⁺.

Step 2:1-(5′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-yl)-pent-4-en-1-one

While under a nitrogen atmosphere, a solution of5′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-carboxylic acid,methoxy-methyl-amide (1.0 g, 3.5 mmol), in tetrahydrofuran (10 mL) wascooled to 0° C. and treated with 4-butenylmagnesiun bromide (0.5 M inTHF, 17.6 mL, 8.8 mmol) dropwise. After stirring for 1 hour at 0° C. androom temperature overnight the reaction mixture was poured into water,acidified to pH 3-4 with 1N hydrochloric acid and extracted with ethylacetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated in vacuo. Purification by flash columnchromatography (silica gel, 0-25% ethyl acetate in heptane) gave1-(5′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-yl)-pent-4-en-1-oneas a colorless oil (904 mg, 93%); ¹H NMR (CDCl₃, 300 MHz) δ 8.05 (d,J=2.5 Hz, 1H), 7.42 (dd, J=9.0 Hz, J₂=2.5 Hz, 1H), 6.62 (d, J=9.0 Hz,1H), 5.80 (m, 1H), 5.04 (m, 2H), 4.23 (m, 2H), 2.92 (m, 2H), 2.59 (m,3H), 2.36 (m, 2H), 1.98 (m, 2H) and 1.70 (m, 2H); MS (+CI): m/z forC₁₅H₁₉ClN₂O: expected 278.1. found 279.2 (M+H)⁺.

Step 3:2-Acetylamino-2-(5′-Chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-yl)-hex-5-enoicacid, tert-butylamide

tert-Butyl isocyanide (538 mg, 0.73 mL, 6.48 mmol) was added to astirred slurry of1-(5′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-yl)-pent-4-en-1-one(900 mg, 3.24 mmol) and ammonium acetate (1.0 g, 12.96 mmol) in2,2,2-trifluoroethanol (0.5 mL). After stirring at room temperature for5 days, the reaction mixture was poured into water and extracted withethyl acetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated in vacuo. Purification by flash columnchromatography (silica gel, 10-40% ethyl acetate in heptane) gave thetitle compound as a white solid (1.02 g, 74%); ¹H NMR (CDCl₃, 300 MHz) δ8.06 (dd, J₁=2.5 Hz, J₂=0.5 Hz, 1H), 7.37 (dd, J₁=9 Hz, J₂=2.5 Hz, 1H),7.01 (br s, NH, 1H), 6.55 (dd, J₁=9.0 Hz, J₂=0.5 Hz, 1H), 5.78 (m, 1H),5.50 (br s, NH, 1H), 4.97 (m, 2H), 4.38 (m, 1H), 4.14 (m, 1H), 3.00(ddd, J₁=14.5 Hz, J₂=11.5 Hz, J₃=5.0 Hz, 1H), 2.72 (td, J₁=13 Hz, J₂=2.5Hz, 2H), 2.44 (tt, J₁=2.5 Hz, J₂=3 Hz, 1H), 1.97-2.08 (m, 1H), 2.00 (s,3H), 1.80 (m, 3H), 1.20-1.52 (m, 3H) and 1.30 (s, 9H).

Step 4:2-acetylamino-2-(5′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-yl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)hexanoicacid, tert-butylamide

A solution of2-acetylamino-2-(5′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-yl)-hex-5-enoicacid, tert-butylamide (1.0 g, 2.38 mmol) in dichloromethane (10 mL) wastreated with chloro-1,5-cyclooctadiene iridium(I) dimer (48 mg, 3 mol %)and 1,2-bis(diphenylphosphino)ethane (57 mg, 6 mol %) under anatmosphere of nitrogen. The solution was stirred at room temperature for30 minutes and then 4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (609 mg,0.69 mL, 4.76 mmol) was added dropwise, and the reaction was thenstirred overnight at room temperature. The reaction was poured intowater and extracted with ethyl acetate (3×). The combined organic phasewas washed with saturated aqueous sodium chloride, dried over anhydrousmagnesium sulfate, filtered and concentrated in vacuo. Purification byflash column chromatography (silica gel, 10-40% ethyl acetate inheptane) gave the title compound as a white solid (1.07 g, 82%); ¹H NMR(CDCl₃, 300 MHz) δ 8.05 (d, J=2 Hz, 1H), 7.35 (dd, J=9.0 Hz, J₂=2.5 Hz,1H), 6.96 (br s, NH, 1H), 6.53 (d, J=9.0 Hz, 1H), 5.78 (m, 1H), 5.46 (brs, NH, 1H), 4.36 (d, J=13 Hz, 1H), 4.12 (d, J=13 Hz, 1H), 2.83 (td,J₁=13.5 Hz, J₂=5 Hz, 1H), 2.72 (td, J₁=12.5 Hz, J₂=2 Hz, 2H), 2.42 (tt,J₁=12 Hz, J₂=3 Hz, 1H), 1.97 (s, 3H), 1.77 (m, 2H), 1.32-1.48 (m, 4H),1.28 (s, 9H), 1.20 (s, 12H), 1.03-1.25 (m, 2H) and 0.72 (t, J=7.5 Hz,2H); MS (+CI): m/z for C₂₈H₄₆BClN₄O₄: expected 548.3. found 549.3(M+H)⁺, 571.3 (M+Na)⁺.

Step 5:2-amino-6-borono-2-(1-(5-chloropyridin-2-yl)piperidin-4-yl)hexanoic acid

A solution of2-acetylamino-2-(5′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyridinyl-4-yl)-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)hexanoicacid, tert-butylamide (1.07 g) in 6 N HCl (20 mL) was stirred at 90° C.for 1 day. After cooling to room temperature, the reaction mixture wastransferred to a separatory funnel, diluted with deionized water (10 mL)and washed with dichloromethane (3×). The aqueous layer was frozen inliquid nitrogen and lyophilized to give title compound as a white solid(590 mg, 82%); ¹H NMR (D₂O, 300 MHz) δ 8.00 (d, J=2.5 Hz, 1H), 7.47 (dd,J₁=9.0 Hz, J₂=2.5 Hz, 1H), 6.79 (d, J=9 Hz, 1H), 4.42 (d, J=13.5 Hz,1H), 4.32 (d, J=13 Hz, 1H), 2.79 (t, J=12 Hz, 2H), 2.06 (m, 1H),1.78-1.94 (m, 3H), 1.55-1.70 (m, 2H), 1.43 (m, 4H), 1.30 (m, 1H) and0.82 (t, J=7 Hz, 2H); MS (+CI): m/z for C₁₆H₂₅BClN₃O₄: expected 369.2.found 370.2 (M+H)⁺, 352.23 (M+H−H₂O)⁺.

Example 86-A: Preparation of2-amino-6-borono-2-(4-(4-chlorophenyl)cyclohexyl)hexanoic acidhydrochloride Step 1: 4-(4-Chlorophenyl)-cyclohexanecarboxylic acid,methoxy-methyl amide

EDC (3.21 g, 16.8 mmol) was added portionwise to a stirred solution of4-(4-chlorophenyl)-cyclohexanecarboxylic acid (2.0 g, 8.4 mmol), DMAP (5mg), HOBt (5 mg) and N,O-dimethylhydroxylamine hydrochloride (1.63 g,16.8 mmol) in dichloromethane (40 mL). Triethylamine (3.4 g, 4.7 mL,33.5 mmol) was added dropwise, and the reaction mixture was stirred atroom temperature. After stirring overnight the reaction mixture waspoured into water and extracted with ethyl acetate (3×). The combinedorganic phase was washed with saturated aqueous sodium chloride, driedover anhydrous magnesium sulfate, filtered and concentrated in vacuo togive 4-(4-chlorophenyl)-cyclohexanecarboxylic acid, methoxy-methyl amideas a colorless oil (1.85 g. 78%); MS (+CI): m/z for C₁₅H₂₀ClNO₂:expected 281.1. found 282.2 (M+H)⁺.

Step 2: 1-[4-(4-Chlorophenyl)-cyclohexyl]pent-4-en-1-one

While under a nitrogen atmosphere, a solution of4-(4-chlorophenyl)-cyclohexanecarboxylic acid, methoxy-methyl amide (1.8g, 6.39 mmol), in tetrahydrofuran (10 mL) was cooled to 0° C. andtreated with 4-butenylmagnesiun bromide (0.5 M in THF, 31.95 mL, 15.98mmol) dropwise. After stirring for 1 hour at 0° C. the reaction mixturewas warmed to room temperature overnight, poured into water, acidifiedto pH 3-4 with 1 N hydrochloric acid and extracted with ethyl acetate(3×). The combined organic phase was washed with saturated aqueoussodium chloride, dried over anhydrous magnesium sulfate, filtered andconcentrated in vacuo. Purification by flash column chromatography(silica gel, 0-20% ethyl acetate in heptane) gave1-[4-(4-chlorophenyl)-cyclohexyl]pent-4-en-1-one as a colorless oil(1.62 g, 92%); ¹H NMR (CDCl₃, 300 MHz) δ 7.26 (m, 2H), 7.12 (d, J=8 Hz,2H), 5.81 (m, 1H), 5.02 (m, 2H), 2.58 (t, J=7 Hz, 2H), 2.44 (m, 2H),2.34 (m, 2H), 1.99 (m, 4H) and 1.47 (m, 4H).

Step 3:2-acetamido-N-tert-butyl-2-(4-(4-chlorophenyl)cyclohexyl)hex-5-enamide

tert-Butyl isocyanide (301 mg, 0.41 mL, 3.6 mmol) was added to a stirredslurry of 1-[4-(4-chlorophenyl)-cyclohexyl]pent-4-en-1-one (800 mg, 2.9mmol) and ammonium acetate (671 mg, 8.7 mmol) in 2,2,2-trifluoroethanol(0.4 mL). After stirring at room temperature for 8 days, the reactionmixture was poured into water and extracted with ethyl acetate (3×). Thecombined organic phase was washed with saturated aqueous sodiumchloride, dried over anhydrous magnesium sulfate, filtered andconcentrated in vacuo. Purification by flash column chromatography(silica gel, 10-50% ethyl acetate in heptane) gave2-acetamido-N-tert-butyl-2-(4-(4-chlorophenyl)cyclohexyl)hex-5-enamideas a colorless oil (940 mg, 77%); ¹H NMR (CDCl₃, 300 MHz) δ 7.24 (m,2H), 7.15 (m, 2H), 7.04 (br s, NH, 1H), 5.80 (m, 1H), 5.544 (br s, NH,1H), 4.97 (m, 2H), 3.04 (ddd, J₁=14 Hz, J₂=11.5 Hz, J₃=5.0 Hz, 1H), 2.38(tt, =12 Hz, J₂=2 Hz, 1H), 2.28 (tt, J₁=12 Hz, J₂=2 Hz, 1H), 2.03 (s,3H), 1.68-1.95 (m, 5H), 1.42-1.61 (m, 4H), 1.41 (s, 9H), 1.26 (m, 1H)and 1.12 (m, 1H); MS (+CI): m/z for C₂₄H₃₅ClN₂O₂: expected 418.2. found419.2 (M+H)⁺.

Step 4.2-acetamido-N-tert-butyl-2-(4-(4-chlorophenyl)cyclohexyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A solution of 2-acetylamino-2-[4-(4-chlorophenyl)-cyclohexyl]hex-5-enoicacid tert-butylamide (940 mg, 2.25 mmol) in dichloromethane (9 mL) wastreated with chloro-1,5-cyclooctadiene iridium(I) dimer (45 mg, 3 mol %)and 1,2-bis(diphenylphosphino)ethane (54 mg, 6 mol %). After stirringfor 30 minutes, 4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (576 mg, 0.65mL, 4.5 mmol) was added dropwise and the stirring was continuedovernight. The reaction was poured into water and extracted with ethylacetate (3×). The combined organic phase was washed with saturatedaqueous sodium chloride, dried over anhydrous magnesium sulfate,filtered and concentrated in vacuo. Purification by flash columnchromatography (silica gel, 10-40% ethyl acetate in heptane) gave2-acetamido-N-tert-butyl-2-(4-(4-chlorophenyl)cyclohexyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamideas a colorless oil (985 mg, 80%); ¹H NMR (CDCl₃, 300 MHz) δ 7.25 (d,J=7.5 Hz, 2H), 7.08 (d, J=7.5 Hz, 2H), 6.99 (br s, NH, 1H), 5.52 (br s,NH, 1H), 2.84 (td, J₁=13 Hz, J₂=3.0 Hz, 1H), 2.37 (t, J=12 Hz, 1H), 2.24(t, J=12 Hz, 1H), 2.00 (s, 3H), 1.90 (m, 4H), 1.20-1.48 (m, 7H), 1.38(s, 9H), 1.22 (s, 12H), 1.06 (m, 2H) and 0.75 (t, J=7.5 Hz, 2H); MS(+CI): m/z for C₃₀H₄₈BClN₂O₄: expected 546.3. found 547.3 (M+H)⁺, 569.3(M+Na)⁺.

Step 5: 2-amino-6-borono-2-(4-(4-chlorophenyl)cyclohexyl)hexanoic acid

A solution of2-acetylamino-2-[4-(4-chlorophenyl)-cyclohexyl]-6-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)hexanoicacid tert-butylamide (980 mg) in 6 N HCl (15 mL) was stirred at 90° C.for 1 day. After cooling to room temperature, the reaction mixture wastransferred to a separatory funnel, diluted with deionized water (10 mL)and washed with dichloromethane (3×). The aqueous layer was frozen inliquid nitrogen and lyophilized to give2-amino-6-borono-2-(4-(4-chlorophenyl)cyclohexyl)hexanoic acid (535 mg,81%). ¹H NMR (D⁴-MeOH, 300 MHz) δ 7.24 (d, J=8.5 Hz, 2H), 7.19 (dd,J=8.5 Hz, 2H), 2.50 (m, 1H), 1.78-2.06 (m, 7H), 1.38-1.56 (m, 7H), 1.21(m, 1H) and 0.82 (t, J=6.5 Hz, 2H); MS (+CI): m/z for C₁₈H₂₇BClNO₄:expected 367.2. found 368.2 (M+H)⁺, 350.2 (M+H−H₂O)⁺.

Example 87-A: Preparation of2-amino-2-(1-benzylpiperidin-4-yl)-6-boronohexanoic acid dihydrochlorideStep 1: benzyl 4-(methoxy(methyl)carbamoyl)piperidine-1-carboxylate

In a 1 L round-bottomed flask, a solution of1-(benzyloxycarbonyl)piperidine-4-carboxylic acid (21.0 g, 80 mmol) inanhydrous dichloromethane (250 mL) was stirred at room temperature untilcompletely dissolved. After becoming clear, the reaction mixture wascooled to 0° C. and sequentially treated with N,O-dimethylhydroxylaminehydrochloride (9.74 g, 100 mmol), EDC (19.2 g, 100 mmol), andtriethylamine (30.4 g, 41.81 mL, 300 mmol). After the additions werecomplete, the reaction mixture was stirred at room temperatureovernight. 1 N HCl (250 mL) was added and after 5 min of additionalstirring, the organic phase was separated, washed with 1 N HCl (100 mL),saturated aqueous NaHCO₃ (150 mL), dried over MgSO₄, filtered andconcentrated. Purification by MPLC (100 g column, 50-100% ethyl acetatein heptane) gave benzyl4-(methoxy(methyl)carbamoyl)piperidine-1-carboxylate (22.23 g, 91%) as acolorless oil. ¹H NMR (CDCl₃, 300 MHz) δ 7.42-7.29 (m, 5H), 5.21 (s,2H), 4.32-4.16 (m, 2H), 3.70 (s, 3H), 3.18 (s, 3H), 2.96-2.78 (m, 3H),1.80-1.64 (m, 4H). ESI MS found for C₁₆H₂₂N₂O₄ m/z [307.1 (M+1), 329.2(M+23)].

Step 2: benzyl 4-pent-4-enoylpiperidine-1-carboxylate

While under an argon atmosphere, a solution of benzyl4-(methoxy(methyl)carbamoyl)piperidine-1-carboxylate (15.0 g, 49.0 mmol)in THF (100 mL) was cooled to −78° C. (dry ice/acetone bath) and treatedwith 3-butenylmagnesium bromide (250 mL, 0.5 M sol. in THF, 125 mmol,Aldrich) via canula. After the addition was complete, the cooling bathwas removed allowing the solution to slowly warm to room temperature.After stirring overnight (16 h), the reaction mixture was quenched with0.1 N HCl (200 mL) and diluted with ethyl acetate (300 mL). Afterstirring an additional 5 min, the organic phase was separated, washedwith saturated sodium bicarbonate (200 mL), dried over MgSO₄, filteredand concentrated. Purification by MPLC (100 g column, 20-50% ethylacetate in heptane) gave benzyl 4-pent-4-enoylpiperidine-1-carboxylate(14.5, 98%) as a colorless oil. ¹H NMR (CDCl₃, 300 MHz) δ 7.38-7.32 (m,5H), 5.79 (dddd, J₁=17.1 Hz, J₂=10.2 Hz, J₃=6.9 Hz, J₄=6.6 Hz, 1H), 5.12(s, 2H), 5.02 (dd, J₁=17.1 Hz, J₂=1.5 Hz, 1H), 4.97 (dd, J₁=10.2 Hz,J₂=1.5 Hz, 1H), 4.28-4.10 (m, 2H), 2.86 (br t, J=12 Hz, 2H), 2.58-2.43(m, 3H), 2.35-2.28 (m, 2H), 1.9-1.74 (m, 2H), 1.62-1.48 (m, 2H). ESI MSfound for C₁₈H₂₃NO₃ m/z [302.3 (M+1), 324.1 (M+23)].

Step 3 benzyl4-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)piperidine-1-carboxylate

A solution of benzyl 4-pent-4-enoylpiperidine-1-carboxylate (10.0 g,33.2 mmol) and ammonium acetate (6.16 g, 80 mmol) in2,2,2-trifluoroethanol (10 mL) was treated with tert-butyl isocyanide(2.57 g, 3.50 mL, 31 mmol). After stirring at room temperature for 14days, the reaction mixture was added to a separatory funnel, dilutedwith water (100 mL) and extracted with ethyl acetate (2×100 mL). Theorganic layer was washed with saturated aqueous sodium chloride, driedover MgSO₄, filtered and concentrated. MPLC purification (100 g column,50-100% ethyl acetate in heptane) gave benzyl4-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)piperidine-1-carboxylateas colorless oil (8.2 g, 56%). ¹H NMR (CDCl₃, 300 MHz) δ 7.36-7.31 (m,5H), 6.98 (bs, 1H), 5.85-5.71 (m, 1H), 5.49 (bs, 1H), 5.11 (s, 2H), 5.00(dd, J₁=16.8 Hz, J₂=1.5 Hz, 1H), 4.95 (dd, J₁=9.9 Hz, J₂=1.5 Hz, 1H),4.36-4.12 (m, 2H), 2.96 (ddd, J₁=14.1 Hz, J₂=11.7 Hz, J₃=5.4 Hz, 1H),2.78-2.61 (m, 2H), 2.37 (ddd, J₁=12.0 Hz, J₂=11.7 Hz, J₃=0.9 Hz, 1H),2.10-1.96 (m, 1H), 2.00 (s, 3H), 1.84-1.64 (m, 3H), 1.56-1.39 (m, 1H),1.39-1.21 (m, 1H), 1.34 (s, 9H), 1.20-1.03 (m, 1H). ESI MS found forC₂₅H₃₇N₃O₄ m/z [444.3 (M+1), 466.1 (M+23)].

Step 4: benzyl4-(2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)piperidine-1-carboxylate

While under an argon atmosphere, a solution of1,2-bis(diphenylphosphino)ethane (306 mg, 0.77 mmol) andchloro-1,5-cyclooctadiene iridium (I) dimer (258 mg, 0.39 mmol) inanhydrous THF (30 mL) was treated with4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.48 g, 1.67 mL, 11.6 mmol) inone portion. After stirring for 15 minutes the solution was cooled to 5°C. (ice-water batch) and treated with benzyl4-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)piperidine-1-carboxylate(3.42 g, 7.70 mmol) in one portion. After the addition was complete, thecooling bath was removed and the reaction mixture was allowed to warm upto room temperature. After 2 hours of stirring the reaction was quenchedwith saturated aqueous sodium bicarbonate (50 mL) and extracted usingethyl acetate (2×150 mL). The organic layer was dried over MgSO₄,filtered and concentrated. MPLC purification (100 g column, 40-80% ethylacetate in heptane) gave benzyl4-(2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)piperidine-1-carboxylateas a colorless oil (3.10 g, 71% yield). ¹H NMR (CDCl₃, 300 MHz) δ7.36-7.30 (m, 5H), 6.94 (bs, 1H), 5.46 (s, 1H), 5.10 (s, 2H), 4.36-4.10(m, 2H), 2.86-2.60 (m, 3H), 2.40-2.28 (bt, J=12.3 Hz, 1H), 1.98 (s, 3H),1.78-1.61 (m, 2H), 1.49-1.17 (m, 5H), 1.33 (s, 9H), 1.20 (s, 8H),1.12-0.94 (m, 2H), 0.73 (t, J=7.8 Hz, 2H).

Step 5:2-acetamido-N-tert-butyl-2-(piperidin-4-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

In a 100 mL round bottom flask while under an argon atmosphere, benzyl4-(2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)piperidine-1-carboxylate(3.0 g, 5.25 mmol) in methanol (40 mL) was degassed with argon (bubbledthrough solution) and subsequently treated with palladium (25 mg, 10 wt% on active carbon, wet, Degussa type E101 NE/W). After continuedbubbling for 10 min the argon was replaced with a slow stream ofhydrogen. After 1.5 h the reaction was complete (reaction monitored byTLC for the disappearance of starting material (50% ethyl acetate inheptane, R_(f) 0.3) and solution was purged with argon, filtered throughthe Celite 545 and the filter cake washed with methanol. The methanolsolution was concentrated and collected solvents evaporated to givecrude2-acetamido-N-tert-butyl-2-(piperidin-4-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(2.20 g 96%) which was used without further purification (containedapproximately 10% product with loss of boronic acid protecting group).¹H NMR (CDCl₃, 300 MHz) δ 6.95 (s, 1H), 5.53 (s, 1H), 3.09 (bt, J=11.1Hz, 2H), 2.80 (ddd, J₁=14.1 Hz, J₂=13.5 Hz, J₃=4.5 Hz, 1H), 2.65-2.48(m, 2H), 2.26 (dddd, J₁=12.0 Hz, J₂=12.0 Hz, J₃=3.0 Hz, J₄=2.7 Hz, 1H),2.00-1.90 (m, 1H), 1.98 (s, 3H), 1.78-1.63 (m, 2H), 1.45-1.00 (m, 5H),1.36 (s, 9H), 1.21 (s, 8H), 0.73 (t, J=7.5 Hz, 2H).

Step 6:2-acetamido-2-(1-benzylpiperidin-4-yl)-N-tert-butyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide

A solution of2-acetamido-N-tert-butyl-2-(piperidin-4-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(480 mg, 1.10 mmol) and benzaldehyde (138 mg, 131 μL, 1.30 mmol) in1,2-dichloroethane (1 mL) was stirred for 20 minutes then treated withsodium triacetoxyborohydride (420 mg, 2.20 mmol). After 5 hours, thereaction mixture was quenched with saturated aqueous sodium bicarbonate(10 mL), diluted with saturated aqueous sodium chloride (50 mL) andextracted with dichloromethane (3×40 mL). Organic layers were collected,dried over MgSO₄, filtered and concentrated. MPLC purification (25 gcolumn, 1-10% methanol in dichloromethane) gave2-acetamido-2-(1-benzylpiperidin-4-yl)-N-tert-butyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamideas a colorless oil (538 mg, 93%), which was used immediately in thesubsequent step (approximately 10% of the product had the boronic aciddeprotected).

Step 7: 2-amino-2-(1-benzylpiperidin-4-yl)-6-boronohexanoic acid

A solution of2-acetamido-2-(1-benzylpiperidin-4-yl)-N-tert-butyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide(510 mg, 0.97 mmol) in 6 N HCl (15 mL) was heated to a gentle reflux for16 h. After cooling to room temperature, the reaction mixture wastransferred to a separatory funnel, diluted with deionized water (15 mL)and washed with dichloromethane (3×25 mL). The aqueous layer wasconcentrated to give an off-white solid that was purified by HPLC (5-95%acetonitrile in water). The fractions containing product wereconcentrated, redissolved in deionized water (15 mL), frozen in liquidnitrogen and lyophilized to give2-amino-2-(1-benzylpiperidin-4-yl)-6-boronohexanoic acid (210 mg, 62%)as its dihydrochloride salt and trihydrate. ¹H NMR (D₂O, 500 MHz) δ7.37-7.43 (m, 5H), 4.21 (s, 2H), 3.51 (brt, J=10 Hz, 2H), 2.92-2.99 (m,2H), 2.02-2.10 (m, 2H), 1.66-1.84 (m, 4H), 1.41 (dq, J₁=13.0 Hz, J₁=4.0Hz, 1H), 1.29-1.35 (m, 2H), 1.23-1.28 (m, 1H), 1.08-1.12 (m, 1H), 0.68(t; J=8.0 Hz, 2H). ESI MS found for C₁₈H₂₉BFN₂O₄ m/z [331.6 (M+1−18)13%, 313.6 (M+1−2×18) 100%, 329.6 (M−1−18) 100%]. Anal. Calcd forC₁₈H₂₉BN₂O₄×2HCl×3H₂O: C, 45.49; H, 7.85; N, 5.89. Found C, 45.60; H,7.10; N, 5.55.

Example 88-A: Preparation of 2-amino-6-borono-2-(piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(piperidin-4-yl)hexanoic acid dihydrochloride isprepared using the synthesis set forth in Example 87-A, except theintermediate from step 5(2-acetamido-N-tert-butyl-2-(piperidin-4-yl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanamide)was directly deprotected as described in step 7. ¹H NMR (D₂O, 300 MHz) δ3.45 (brd, J=12.0 Hz, 2H), 2.92-2.98 (m, 2H), 2.15 (brt, J=12.0 Hz, 1H),2.04 (brd, J=14.0 Hz, 1H), 1.79-1.86 (m, 3H), 1.71 (dq, J₁=13.0 Hz,J₂=3.0 Hz, 1H), 1.43 (dq, J₁=13.0 Hz, J₂=3.0 Hz, 1H), 1.27-1.38 (m, 3H),1.09-1.17 (m, 1H), 0.71 (t, J=8.0 Hz, 2H). ESI MS found for C₁₁H₂₃BN₂O₄m/z [281.5 (M+Na⁺) 3%, 263.5 (M+Na⁺-18) 5%, 241.5 (M+1−18) 15%, 223.4(M+1−2×18) 100%].

Example 89-A: Preparation of2-amino-6-borono-2-(1-(4-chlorobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(4-chlorobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 87-A, except 4-chlorobenzaldehyde is used as the aldehyde instep 6. ¹H NMR (D₂O, 300 MHz) δ 7.31 (d_(AB), J=8.4 Hz, 2H), 7.25(d_(AB), J=8.4 Hz, 2H), 4.11 (s, 2H), 3.47-3.35 (m, 2H), 2.93-2.80 (m,2H), 2.09 (bt, J=12.3 Hz, 1H), 1.92 (d, J=13.8 Hz, 1H), 1.84-1.60 (m,4H), 1.45-1.31 (m, 1H), 1.30-1.13 (m, 3H), 1.10-0.95 (m, 1H), 0.59 (t,J=7.2 Hz, 2H). ESI MS found for C₁₈H₂₈BClN₂O₄ m/z [383.2 (M+1)].

Example 90-A: Preparation of2-amino-2-(1-(benzo[d][1,3]dioxol-5-ylmethyl)piperidin-4-yl)-6-boronohexanoicacid dihydrochloride

2-Amino-2-(1-(benzo[d][1,3]dioxol-5-ylmethyl)piperidin-4-yl)-6-boronohexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 87-A, except benzo[d][1,3]dioxole-5-carbaldehyde is used asthe aldehyde in step 6. ¹H NMR (D₂O, 300 MHz) δ 6.87-6.74 (m, 3H), 5.85(s, 2H), 4.05 (s, 2H), 3.50-3.32 (m, 2H), 2.95-2.75 (m, 2H), 2.04-1.90(m, 2H), 1.80-1.60 (m, 4H), 1.50-0.95 (m, 5H), 0.62 (t, J=7.2 Hz, 2H).ESI MS found for C₁₉H₂₉BN₂O₆ m/z [393.2 (M+1)].

Example 91-A: Preparation of2-amino-6-borono-2-(1-((6-chlorobenzo[d][1,3]dioxol-5-yl)methyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-((6-chlorobenzo[d][1,3]dioxol-5-yl)methyl)piperidin-4-yl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 87-A, except 6-chlorobenzo[d][1,3]dioxole-5-carbaldehyde isused as the aldehyde in step 6. ¹H NMR (D₂O, 500 MHz) δ 6.98, (s, 1H),6.94, (s, 1H), 5.97 (s, 2H), 4.29 (s, 2H), 3.58 (t, J=11.6 Hz, 2H),3.11-3.05 (m, 2H), 2.15-2.04 (m, 2H), 1.50-1.42 (m, 1H), 1.36-1.25 (m,3H), 1.14-1.07 (m, 1H), 0.69 (t, J=7.6 Hz, 2H). ESI MS found forC₁₉H₂₈BClN₂O₆ m/z [409.6/411.6 (M+1−18) 10%, 391.5/393.5 (M+1−2×18) 63%,425.5/427.5 (M−1) 27%, 407.6/409.6 (M−1−18) 100%].

Example 92-A: Preparation of2-amino-6-borono-2-(1-isopentylpiperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-isopentylpiperidin-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 87-A, except isopentanal (3-methylbutanal) is used as thealdehyde in step 6. ¹H NMR (D₂O, 500 MHz) δ 3.55 (t, J=11.7 Hz, 2H),3.00-2.97 (m, 2H), 2.88-2.82 (m, 2H), 2.11-2.01 (m, 2H), 1.84-1.70 (m,4H), 1.52-1.38 (m, 4H), 1.33-1.21 (m, 3H), 1.10-1.03 (m, 1H), 0.77 (d,J=5.5 Hz, 6H), 0.66 (t, J=7.6 Hz, 2H). ESI MS found for C₁₆H₃₃BN₂O₄ m/z[329.7 (M+1) 2%, 311.6 (M+1−18) 20%, 293.6 (M+1−2×18) 100%, 327.7 (M−1)10%, 309.6 (M−1−18) 100%].

Example 93-A: Preparation of2-amino-6-borono-2-(1-(4-(trifluoromethyl)benzyl)piperidin-4-yl)hexanoicacid

2-Amino-6-borono-2-(1-(4-(trifluoromethyl)benzyl)piperidin-4-yl)hexanoicacid is prepared in a manner analogous to that set forth in Example87-A, except 4-(trifluoromethyl)benzaldehyde is used as the aldehyde instep 6. ¹H NMR (D₂O, 400 MHz) δ 7.76-7.70 (m, 2H), 7.65-7.54 (m, 2H),4.25 (s, 2H), 3.60-3.37 (m, 2H), 3.07-2.84 (m, 2H), 2.07-1.95 (m, 2H),1.82 (s, 3H), 1.81-1.63 (m, 4H), 1.47-1.16 (m, 4H), 1.14-1.00 (m, 1H),0.67 (t, J=8.29 Hz, 2H) MS found for C₁₉H₂₈BF₃N₂O₄ m/z[399.1,(M−18+1),381.1 (M−36+1)].

Example 94-A: Preparation of2-amino-6-borono-2-(1-(4-fluorobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(4-fluorobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 87-A, except 4-fluorobenzaldehyde is used as the aldehyde instep 6. ¹H NMR (D₂O, 400 MHz) δ 7.42-7.35 (m, 2H), 7.16-7.07 (m, 2H),4.19 (s, 2H), 3.60-3.35 (m, 2H), 3.06-2.81 (m, 2H), 2.07-1.94 (m, 2H),1.86 (s, 3H), 1.84-1.60 (m, 4H), 1.45-1.16 (m, 4H), 1.14-0.99 (m, 1H),0.68 (t, J=8.3 Hz, 2H). MS found for C₁₈H₂₈BFN₂O₄ m/z[349.1, (M−18+1),331.1 (M−36+1)].

Example 95-A: Preparation of2-amino-6-borono-2-(1-(3,4-dichlorobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(3,4-dichlorobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 118, except 3,4-dichlorobenzaldehyde is used as the aldehyde instep 6. ¹H NMR (D₂O, 400 MHz) δ 7.56-7.50 (m, 2H), 7.29-7.24 (m, 1H),4.16 (s, 2H), 3.57-3.32 (m, 2H), 3.01-2.76 (m, 2H), 2.05-1.95 (m, 2H),1.80 (s, 3H), 1.79-1.63 (m, 4H), 1.45-1.15 (m, 4H), 1.14-0.99 (m, 1H),0.68 (t, J=8.29 Hz, 2H) MS found for C₁₈H₂₇BCl₂N₂O₄ m/z[399.2, (M−18+1),381.2 (M−36+1)].

Example 96-A: Preparation of2-amino-6-borono-2-(1-(2-fluoro-4,5-dimethoxybenzyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(2-fluoro-4,5-dimethoxybenzyl)piperidin-4-yl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 87-A, except 2-fluoro-4,5-dimethoxybenzaldehyde is used asthe aldehyde in step 6. ¹H NMR (D₂O, 400 MHz) δ 6.97 (d, J=7.1 Hz, 1H),6.89 (d, J=7.1 Hz, 1H), 4.02 (s, 2H), 3.82 (s, 3H), 3.79 (s, 3H),3.47-3.34 (m, 2H), 2.85-2.69 (m, 2H), 2.05-1.90 (m, 2H), 1.85 (s, 3H),1.81-1.61 (m, 4H), 1.45-1.22 (m, 4H), 1.20-1.08 (m, 1H), 0.72 (t, J=8.3Hz, 2H). MS found for C₂₀H₃₂BFN₂O₆ m/z[409.2, (M−18+1), 391.2 (M−36+1)].

Example 97-A: Preparation of2-amino-6-borono-2-(1-(2,4-dichlorobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(2,4-dichlorobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 87-A, except 2,4-dichlorobenzaldehyde is used as the aldehyde instep 6. ¹H NMR (D₂O, 400 MHz) δ 7.66 (d, J=2.0 Hz, 1H), 7.53 (s, 1H),7.47 (d, J=2.1 Hz, 1H), 4.46 (s, 2H), 3.71-3.61 (m, 2H), 3.26-3.12 (m,2H), 2.18-2.07 (m, 2H), 1.90-1.76 (m, 3H), 1.61-1.47 (m, 1H), 1.46-1.19(m, 3H), 1.25-1.11 (m, 1H), 0.77 (t, J=7.4 Hz, 2H). ESI⁺/ESI⁻ MS: obsdm/z 400.1 (M−18+H)⁺, 381.1 (M−36+H)+, 399.1 (M−18−1)⁻, 381.1 (M−36−1)⁻.

Example 98-A: Preparation of2-amino-6-borono-2-(1-(naphthalen-1-ylmethyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(naphthalen-1-ylmethyl)piperidin-4-yl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 87-A, except 1-naphthaldehyde is used as the aldehyde in step6. ¹H NMR (D₂O, 400 MHz) δ 8.15 (d, J=8.4 Hz, 1H), 8.09 (d, J=8.4 Hz,1H), 8.05 (d, J=8.4 Hz, 1H), 7.74-7.58 (m, 4H), 4.81 (s, 2H), 3.71-3.56(m, 2H), 3.27-3.11 (m, 2H), 2.19-2.03 (m, 2H), 1.90-1.70 (m, 4H),1.57-1.27 (m, 4H), 1.25-1.09 (m, 1H), 0.77 (t, J=7.6 Hz, 2H). ESI⁺/ESI⁻MS: obsd m/z 381.1 (M−18+H)⁺, 363.1 (M−36+H)+, 379.1 (M−18−1)⁻.

Example 99-A: Preparation of2-amino-6-borono-2-(1-(naphthalen-2-ylmethyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(naphthalen-2-ylmethyl)piperidin-4-yl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 87-A, except 2-naphthaldehyde is used as the aldehyde in step6. ¹H NMR (D₂O, 400 MHz) δ 8.04-7.96 (m, 4H), 7.67-7.57 (m, 2H), 7.55(d, J=8.4 Hz, 1H), 4.41 (s, 2H), 3.65-3.52 (m, 2H), 3.11-2.95 (m, 2H),2.16-2.04 (m, 2H), 1.87-1.70 (m, 4H), 1.57-1.27 (m, 4H), 1.25-1.11 (m,1H), 0.77 (t, J=7.6 Hz, 2H). ESI⁺/ESI⁻ MS: obsd m/z 381.1 (M−18+H)⁺,363.1 (M−36+H)+, 379.1 (M−18−1)⁻.

Example 100-A: Preparation of2-amino-6-borono-2-(1-(4-(trifluoromethoxy)benzyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(4-(trifluoromethoxy)benzyl)piperidin-4-yl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 87-A, except 4-(trifluoromethoxy)benzaldehyde is used as thealdehyde in step 6. ¹H NMR (D₂O, 400 MHz) δ 7.55 (d, J=8.8 Hz, 2H), 7.41(d, J=8.8 Hz, 2H), 4.28 (s, 2H), 3.60-3.50 (m, 2H), 3.06-2.92 (m, 2H),2.14-2.04 (m, 2H), 1.88-1.73 (m, 4H), 1.56-1.28 (m, 4H), 1.25-1.11 (m,1H), 0.77 (t, J=7.6 Hz, 2H). ¹⁹F NMR (D₂O, 400 MHz) δ −57.9 (s, 3F).ESI⁺/ESI⁻ MS: obsd m/z 415.2 (M−18+1)⁺, 397.2 (M−36+1)+, 413.2(M−18−1)⁻.

Example 101-A: Preparation of2-amino-6-borono-2-(1-propylpiperidin-4-yl)hexanoic acid dihydrochloride

2-Amino-6-borono-2-(1-propylpiperidin-4-yl)hexanoic acid dihydrochlorideis prepared in a manner analogous to that set forth in Example 87-A,except propionaldehyde is used as the aldehyde in step 6. ¹H NMR (D₂O,500 MHz) δ 3.51 (t, J=11.0 Hz, 2H), 2.91-2.88 (m, 2H), 2.86-2.81 (m,2H), 2.10 (t, J=12.4 Hz, 1H), 2.00 (d, J=13.7 Hz, 1H), 1.83-1.67 (m,4H), 1.59-1.52 (m, 2H), 1.46-1.37 (m, 1H), 1.30-1.20 (m, 3H), 1.07-1.00(m, 1H), 0.77 (t, J=7.6 Hz, 3H), 0.62 (t, J=7.6 Hz, 2H). ESI MS foundfor C₁₄H₂₉BN₂O₄ m/z [301.5 (M+1) 1%, 283.5 (M+1−18) 17%, 265.5(M+1−2×18) 100%, 581.9 (2M−1−18) 13%, 299.6 (M−1) 25%, 281.5 (M−1−18)100%].

Example 102-A: Preparation of2-amino-6-borono-2-(1-(3-phenylpropyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(3-phenylpropyl)piperidin-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 87-A, except 3-phenylpropanal is used as the aldehyde in step 6.¹H NMR (D₂O, 500 MHz) δ 7.30 (d, J=7.6 Hz, 1H), 7.29 (d, J=7.6 Hz, 1H),7.21-7.20 (m, 3H), 3.56 (t, J=11.6 Hz, 2H), 3.02-2.99 (m, 2H), 2.90-2.83(m, 2H), 2.62 (t, J=7.6 Hz, 2H), 2.12-2.04 (m, 2H), 1.99-1.93 (m, 2H),1.86-1.74 (m, 4H), 1.49-1.41 (m, 1H), 1.37-1.24 (m, 3H), 1.14-1.08 (m,1H), 0.70 (t, J=7.6 Hz, 2H). ESI MS found for C₂₀H₃₃BN₂O₄ m/z [359.6(M+1−18) 15%, 341.6 (M+1−2×18) 100%, 734.0 (2M−1−18) 15%, 375.6 (M−1)11%, 357.6 (M−1−18) 100%]. Anal. Calcd for C₂₀H₃₃BN₂O₄×2HCl×2H₂O: C,49.50; H, 8.10; N, 5.77. Found C, 49.50; H, 8.49; N, 5.86.

Example 103-A: Preparation of2-amino-6-borono-2-(1-(3-(trifluoromethoxy)benzyl)piperidin-4-yl)hexanoicacid dihydrochloride

2-Amino-6-borono-2-(1-(3-(trifluoromethoxy)benzyl)piperidin-4-yl)hexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 87-A, except 3-(trifluoromethoxy)benzaldehyde is used as thealdehyde in step 6. ¹H NMR (D₂O, 400 MHz) δ 7.54 (t, J=7.8 Hz, 1H),7.45-7.38 (m, 3H), 4.14 (s, 2H), 3.51-3.37 (m, 2H), 2.92-2.76 (m, 2H),2.11-1.98 (m, 2H), 1.86-1.65 (m, 4H), 1.50-1.28 (m, 4H), 1.24-1.10 (m,1H), 0.77 (t, J=7.6 Hz, 2H). ¹⁹F NMR (D₂O, 400 MHz) δ −57.9 (s, 3F),ESI⁺/ESI⁻ MS: obsd m/z 415.1 (M−18+H)⁺, 397.1 (M−36+H)+, 413.1(M−18−1)⁻.

Example 104-A: Preparation of2-amino-2-(1-(benzo[b]thiophen-3-ylmethyl)piperidin-4-yl)-6-boronohexanoicacid dihydrochloride

2-Amino-2-(1-(benzo[b]thiophen-3-ylmethyl)piperidin-4-yl)-6-boronohexanoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 87-A, except benzo[b]thiophene-3-carbaldehyde is used as thealdehyde in step 6. ¹H NMR (D₂O, 400 MHz) δ 8.05 (d, J=7.7 Hz, 1H),7.95-7.92 (m, 2H), 7.58-7.47 (m, 2H), 4.61 (s, 2H), 3.70-3.60 (m, 2H),3.21-3.08 (m, 2H), 2.16-2.05 (m, 2H), 1.92-1.74 (m, 4H), 1.58-1.26 (m,4H), 1.23-1.10 (m, 1H), 0.77 (t, J=7.6 Hz, 2H). ESI⁻/ESI⁻ MS: obsd m/z387.1 (M−18+H)⁺, 369.1 (M−36+H)+, 385.1 (M−18−1)⁻.

Example 105-A: Preparation of3-((4-(1-amino-5-borono-1-carboxypentyl)piperidin-1-yl)methyl)benzoicacid dihydrochloride

3-((4-(1-Amino-5-borono-1-carboxypentyl)piperidin-1-yl)methyl)benzoicacid dihydrochloride is prepared in a manner analogous to that set forthin Example 87-A, except tert-butyl 3-formylbenzoate is used as thealdehyde in step 6. ¹H NMR (D₂O, 400 MHz) δ 7.84 (d, J=8.7 Hz, 1H), 7.79(s, 1H), 7.52-7.42 (m, 2H), 4.25 (s, 2H), 3.55-3.43 (m, 2H), 3.05-2.89(m, 2H), 2.09-1.79 (m, 2H), 1.83 (s, 3H), 1.80-1.65 (m, 6H), 1.49-1.35(m, 1H), 1.35-1.71 (m, 1H), 1.14-0.99 (m, 1H), 0.67 (t, J=8.3 Hz, 2H).MS found for C₁₉H₂₉BN₂O₆ m/z[375.1, (M−18+1), 357.1 (M−36+1)].

Example 106-A: Preparation of2-amino-6-borono-2-(1-(3-cyanobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride

2-Amino-6-borono-2-(1-(3-cyanobenzyl)piperidin-4-yl)hexanoic aciddihydrochloride is prepared in a manner analogous to that set forth inExample 87-A, except 3-formylbenzonitrile is used as the aldehyde instep 6. ¹H NMR (D₂O, 400 MHz) δ 7.82-7.76 (m, 2H), 7.69 (d, J=7.4 Hz,1H), 7.56 (t, J=8.0 Hz, 1H), 4.19 (s, 2H), 3.49-3.36 (m, 2H), 2.91-2.78(m, 2H), 2.06-1.94 (m, 2H), 1.81 (s, 3H), 1.80-1.62 (m, 4H), 1.46-1.19(m, 4H), 1.16-1.03 (m, 1H), 0.69 (t, J=8.29 Hz, 2H). MS found forC₁₉H₂₈BN₃O₄ m/z[356.2 (M−18+1), 338.2 (M−36+1)].

Methods and Uses

Inventive Formula I and Formula II compounds are useful for inhibitingthe expression or activity of arginase I, arginase II or a combinationof these enzymes. The enzymes of the arginase family play an importantrole in regulating the physiological levels of the L-arginine, aprecursor of the signaling molecule nitric oxide (nitric oxide (NO)), aswell as in regulating levels of L-ornithine, a precursor of certainpolyamines that are important physiological signal transducers.

More specifically, the invention provides methods and uses forinhibiting arginase I, arginase II, or a combination thereof in a cell,comprising contacting the cell with at least one compound according toFormula I or Formula II, or composition thereof as described herein. Insome embodiments, the invention provides a method for the treatment orprevention of a disease or condition associated with expression oractivity of arginase I, arginase II, or a combination thereof in asubject.

For instance, the disease or condition is selected from the groupconsisting of heart disease, hypertension, sexual disorders, gastricdisorders, autoimmune disorders, parasitic infections, pulmonarydisorders, smooth muscle relaxation disorders and hemolytic disorders.

More specifically, hypertension includes systemic hypertension,pulmonary arterial hypertension (PAH), and pulmonary arterialhypertension in high altitude.

Exemplary sexual disorders are disease or conditions selected from thegroup consisting of Peyronie's Disease and erectile dysfunction (ED).

In one embodiment an arginase inhibitor in accordance with the presentinvention is suitable for treating a pulmonary disorder selected fromthe group consisting of chemically-induced lung fibrosis, idiopathicpulmonary fibrosis, cystic fibrosis, chronic obstructive pulmonarydisease (COPD.

Compounds in accordance with the present invention are also useful fortreating gastrointestinal disorders, such as diseases or conditionsselected from the group consisting of gastrointestinal motilitydisorders, gastric cancers, reduced hepatic blood flow disorders,inflammatory bowel disease, Crohn's disease, ulcerative colitis, andgastric ulcers.

The transport of organs increases the risk of ischemia reperfusion (IR)injury, such as liver IR kidney IR, and myocardial IR. Formula I orFormula II compounds in accordance with the present invention are usefulin protecting organs during organ transport.

In another embodiment, inhibitors of arginase in accordance with thepresent invention are used to treat hemolytic disorders selected fromthe group consisting of paroxysmal nocturnal hemoglobinuria (PNH),sickle-cell disease, thalassemias, hereditary spherocytosis andstomatocytosis, microangiopathic hemolytic anemias, pyruvate kinasedeficiency, ABO mismatch transfusion reaction, paroxysmal coldhemoglobinuria, severe idiopathic autoimmune hemolytic anemia,infection-induced anemia, cardiopulmonary bypass, mechanical heartvalve-induced anemia and chemical induced anemia. In addition, thecompounds described herein are useful in the treatment of malaria.

The inventive compounds are useful in the treatment of autoimmunediseases selected from the group consisting of encephalomyelitis,multiple sclerosis, anti-phospholipid syndrome 1, autoimmune hemolyticanaemia, chronic inflammatory demyelinating polyradiculoneuropathy,dermatitis herpetiformis, dermatomyositis, myasthenia gravis, pemphigus,rheumatoid arthritis, stiff-person syndrome, type 1 diabetes andankylosing spondylitis. In another embodiment, Formulae I or IIcompounds are useful for treating immune disorders selected from thegroup consisting of immune-response, T-cell dysfunction, such asmyeloid-derived suppressor cell (MDSC) mediated T-cell dysfunction,human immunodeficiency virus (HIV) and autoimmune encephalomyelitis.

Other exemplary disease conditions for which compounds described hereinare candidate therapeutics are African sleeping sickness, Chagas'disease, smooth muscle relaxation disorders, for example, disorders ofsmooth muscle selected from the group consisting of a gastrointestinalsmooth muscle, anal sphincter smooth muscle, esophageal sphinctermuscle, corpus cavernosum, sphincter of Oddi, arterial smooth muscle,heart smooth muscle, pulmonary smooth muscle, kidney smooth muscle,uterine smooth muscle, vaginal smooth muscle, cervical smooth muscle,placental smooth muscle, and ocular smooth muscle disorder.

The increased levels of arginase in certain cancer patients implicates atherapeutic role for the inventive arginase inhibitors in the treatmentof certain cancers, for example, renal cell carcinoma, prostate cancer,colorectal cancer, breast cancer, skin cancer, lung cancer, ovariancancer, gastric cancer.

Advantageously, the compounds of the invention are especially useful intreating conditions or disorders selected from the group consisting ofarthritis, myocardial infarction and atherosclerosis, renal disease,asthma, inflammation, psoriasis, leishmaniasis, sickle cell disease(SCD), neurodegenerative diseases, wound healing, such as infected anduninfected wound healing, hepatitis B virus (HBV), H. pylori infections,fibrotic diseases such as cystic fibrosis, candidiasis, periodontaldisease, keloids, adenotonsilar disease, cerebral vasospasm, andGoodpasture's syndrome.

In some embodiments, the subject receiving treatment is a mammal. Forinstance, the methods and uses described herein are suitable for medicaluse in humans. Alternatively, the methods and uses are also suitable ina veterinary context, wherein the subject includes but is not limited toa dog, cat, horse, cow, sheep, lamb and reptile.

More specific descriptions of diseases and conditions follow below.

Erectile Dysfunction

The observation that there are differences in the activity of arginasein the penis of young mice versus older mice led to the conclusion thatarginase may play a role in erectile dysfunction (ED). In this context,Champion et. al., (Am. J. Physiol. Heart Circ. Physiol. 292:340-351,(2006) and Biochem. and Biophys. Research Communications, 283:923-27,(2001)), observed an increase of mRNA expression levels and arginaseprotein in aged mice along with a reduction in the activity ofconstitutively active NOS.

Nitric oxide is implicated in nonadrenergic, noncholinergicneurotransmission that leads to smooth-muscle relaxation in the corpuscavernosum enabling penile erection (New England Journal of Medicine,326, (1992)), Hence, erectile dysfunction can often be treated byelevating penile tissue nitric oxide (NO) levels. Such an elevation intissue nitric oxide (NO) levels can be achieved by inhibiting arginaseactivity in penile tissue of aged subjects. Stated differently, arginasehas been postulated to deplete the pool of free L-arginine available toNOS in cells which results in lower levels of nitric oxide (NO) anderectile dysfunction. See, Christianson et. al., (Acc. Chem. Res.,38:191-201, (2005)), and (Nature Structural Biol., 6(11):1043-1047,(1999)). Inhibitors of arginase, therefore, can play a role in thetreatment of erectile dysfunction.

Pulmonary Hypertension

It has been proposed that alterations in arginine metabolism areinvolved in the pathogenesis of pulmonary hypertension (Xu et al., FASEBJ., 18:1746-48, 2004). The proposition is based in part on the findingthat arginase II expression and arginase activity are significantlyelevated in pulmonary artery endothelial cells derived from lungexplants of patients with class I pulmonary hypertension.

Additionally, secondary pulmonary hypertension is emerging as one of theleading causes of mortality and morbidity in patients suffering fromhemolytic anemias, such as thalassemia and sickle cell disease. Theunderlying cause for secondary pulmonary hypertension is impaired nitricoxide bioavailability due to release of arginase following hemolysiswhich decreases the pool of free arinine that is required for nitricoxide (NO) synthesis. Accordingly, inhibition of arginase activity canprovide a potential therapeutic avenue for treating pulmonaryhypertension.

Hypertension

Xu, W. et al., FASEB 2004, 14, 1746-8 proposed a fundamental role ofarginase II in blood pressure regulation. In this context, high levelsof vascular arginase are correlated to concomitant reduction of vascularnitric oxide (NO) in hypertensive animals. For instance, up-regulationof arginase activity precedes a rise in blood pressure in rats that weregenetically predisposed to hypertension (i.e., spontaneouslyhypertensive rats), but administration of the anti-hypertensive agenthydralazine lowered blood pressure with a decrease in the expressionlevels of vascular arginase, thereby indicating a strong correlationbetween the arginase activity and blood pressure (Berthelot et al. LifeSciences, 80:1128-34, (2008). Similar administration of the knownarginase inhibitor N^(ω)-hydroxy-nor-L-arginine (nor-NOHA) lowered bloodpressure and improved the vascular response of resistance vessels toblood flow and pressure in spontaneously hypertensive animals, therebyhighlighting inhibitors of arginase as candidate therapeutics fortreating hypertension (Demougeot et al., (J. Hypertension, 26:1110-18,(2008).

Arginase also plays a role in reflex cutaneous hypertension by loweringthe cellular levels of nitric oxide (NO). Nitric oxide causesvasodilation and levels of nitric oxide (NO) are normally elevated orlowered to maintain blood pressure at physiologically acceptable levels.Kenny et al., (J. of Physiology 581 (2007) 863-872), hypothesized thatreflex vasodilation in hypertensive subjects can attenuate arginaseinhibition, thereby implicating a role for arginase inhibitors for thetreatment of hypertension.

Asthma

Arginase activity is also associated with airway hyperresponsiveness inasthma. For example, arginase I is upregulated in human asthmatics andin mice suffering from acute and chronic asthma, whilst levels ofarginase II and NOS isoforms remain unchanged (Scott et al., Am. J.Physiol. Lung Cell Mol. Physiol. 296:911-920 (2009)). Furthermore,methacholine induced responsiveness of the central airways in the murinechronic model attenuated upon the administration of the arginaseinhibitor S-(2-boronoethyl)-L-cysteine. The similarity betweenexpression profiles of ARG I in humans and in mice having chronic asthmaindicates that compounds capable of inhibiting arginase activity arecandidate therapeutics for treating asthma.

Other lines of evidence reveal further correlations between increasedactivity of arginase in asthmatic lung tissue and disease progression,such as an upregulation for genes related to the metabolism of cationicamino acids, including arginase I and II in mice having asthma(Rothenberg et al., (J. Clin. Invest., 111:1863-74 (2003), and Meurs et.al., (Expert Opin. Investig Drugs, 14(10:12211231, (2005)).

Further, levels of all amino acids are lower in the plasma ofasthmatics, but the levels of arginine are significantly lower in plasmacompared to that of a normal subject (Morris et al., (Am. J. Respir.Crit. Care Med., 170:148-154, (2004)). Thus, arginase activity issignificantly increased in the plasma from an asthmatic, in whichelevated levels of arginase activity may contribute to the lowerbioavailability of plasma arginine that creates an nitric oxide (NO)deficiency, which is responsible for promoting hyperreactive airways inasthmatics.

Inflammation

Arginase activity also is associated with autoimmune inflammation (Chenet al., Immunology, 110:141-148, (2003)). The authors identifiedupregulation in the expression levels of the ARG I gene in murine spinalcells from animals undergoing experimental autoimmune encephalomyelitis(EAE). Administration of the arginase inhibitor amino-6-boronohexanoicacid (ABH), however, resulted in the animals developing a much milderform of EAE than in control animals. These results implicate inhibitorsof arginase in a therapeutic role for treating autoimmuneencephalomyelitis.

Moreover, Horowitz et al., (American J. Physiol Gastrointestinal LiverPhysiol., 292:G1323-36, (2007)), suggest a role for arginase enzymes invascular pathophysiology. For example, these authors indicate a loss ofnitric oxide (NO) production in chronically inflamed gut blood vesselsin patients suffering from irritable bowel disease (IBD), Crohn'sdisease and ulcerative colitis. The loss in nitric oxide (NO) productioncorrelated with an upregulation of arginase expression and activity thatreduced levels of arginine preventing nitric oxide synthase (NOS), fromsynthesizing nitric oxide (NO) Inhibitors of arginase activity,therefore, may be candidate therapeutics for treating vascularpathophysiology.

Ischaemia Reperfusion

Arginase inhibition is also suggested to play a cardioprotective roleduring ischaemia reperfusion. More specifically, inhibition of arginaseprotects against myocardial infarction by a mechanism that may bedependent on NOS activity and the consequent bioavailability of nitricoxide (NO) (Pernow et al., (Cardiovascular Research, 85:147-154 (2010)).

Myocardial Infarction and Artherosclerosis

Arginase I polymorphism is associated with myocardial infarction alongwith an increased risk of developing carotid artery intima mediathickness that is considered to be a reliable indicator ofarthrosclerosis as well as of other coronary arterial diseases(Brousseau et al., (J. Med Genetics, 44:526-531, (2007)). Increasedarginase activity elevates levels of ornithine that is biochemicallyinvolved in promoting the formation of the matrix and cellularcomponents of artherosclerotic plaque. Id. Thus, arginase inhibitors mayserve as candidate therapeutics for treating artherosclerosis. Berkowitzet al., (Circulation Res. 102, (2008)), implicated a role for ARGII inthe formation of plaque and artherosclerosis. Oxidation of LDLP thataccompanies plaque formation increases arginase activity and lowernitric oxide (NO) levels in endothelial cells. In particular, levels ofARGII are elevated in artherosclerotic mice, indicating a role forinhibitors of arginase as candidate therapeutics for treatingartherosclerosis.

Additionally, studies by Ming et. al., (Current Hypertension Reports.,54:54-59, (2006)), indicate that an upregulation of arginase rather thanendothelial nitric oxide (NO) dysfunction plays an important role incardiovascular disorders, including artherosclerosis. That arginase isinvolved in cardiovascular diseases is further supported by theobservation ARGI and ARGII activity is upregulated in cardiac myocyteswhich in turn negatively impacts NOS activity and myocardialcontractility. (See, Margulies et. al., Am. J. Physiol. Heart Circ.Physiol., 290:1756-62, (2006)).

Immune Response

The arginine/nitric oxide (NO) pathway may also play a role in immuneresponse, such as after organ transplants. For instance, it waspostulated that reperfusion of an orthotopic liver transplant graftcaused a significant increase in ornithine levels due to upregulation ofarginase activity in the graft (Tsikas et al., (Nitric oxide, 20:61-67,(2009)). The elevated levels of hydrolytic and proteolytic enzymes inthe graft may result in a less favorable outcome for the grafted organ.Thus, inhibiting the arginase enzymes may present an alternatetherapeutic avenue for improving the outcome of a transplant.

Psoriasis

Arginase has been implicated to play a role in the pathogenesis ofpsoriasis. For example, ARG I is highly expressed in hyperproliferativepsoriasis, and in fact, it is responsible for down regulation of nitricoxide (NO) an inhibitor of cell proliferation, by competing for thecommon substrate L-arginine as postulated by D. Bruch-Gerharz et al.American Journal of Pathology 162(1) (2003) 203-211. More recent work byAbeyakirthi et al. (British J. Dermatology, (2010)), and Berkowitz etal, (WO/2007/005620) support the finding of low nitric oxide (NO) levelsin psoriatic keratinocytes. Abeyakirthi et al, found that psoriatickeratinocytes were poorly differentiated and hyperproliferative. Thepoor differentiation was postulated to result from low levels of nitricoxide (NO), not because of poor expression of NOS, but rather the overexpression of arginase that competes with NOS for substrate L-arginine.Thus, inhibition of arginase may provide therapeutic relief frompsoriasis.

Wound Healing

Under normal physiological conditions, nitric oxide (NO) plays animportant role in promoting wound healing. For example, Hulst et al.,(Nitric Oxide, 21:175-183, (2009)), studied the role of ARGI and ARG IIin wound healing. Immediately following injury, it is desirable toelevate tissue levels of nitric oxide (NO) so as to promote angiogenesisand cell proliferation that are important for healing Inhibitors ofarginase may therefore find use as therapeutics to treat wounds becausesuch compounds would elevate tissue levels of nitric oxide (NO). Furthersupport for the use of arginase inhibitors as candidate therapeutics fortreating wounds was provided by South et al. (Experimental Dermatology,29:664-668 (2004)), who found a 5-fold increase in arginase I in chronicwounds such as skin erosions and blisters.

Cystic Fibrosis

Cystic fibrosis (CF) is a multisystem disorder caused by mutations ofthe cystic fibrosis transmembrane conductance regulator (CFTR) gene. Thecommon symptoms of CF are persistent pulmonary infection, difficulty inbreathing, pancreatic insufficiency, and elevated sweat chloride levels.CF can be fatal if untreated, with pulmonary diseases, resulting frommucus build-up and decreased mucociliary clearance, being the leadingcause of morbidity and mortality.

It has been asserted that patients with cystic fibrosis (CF) haveincreased plasma and sputum arginase activity, with an accompanyingdecrease in the levels of plasma 1-arginine (H. Grasemann et al., Am. J.Respir. Crit. Care Med. 172(12) (2005) 1523-1528. The increased arginaseactivity, however, results in lower physiological levels of nitric oxide(NO) that can cause airway obstruction decreased pulmonary function inpatients suffering from cystic fibrosis (CF).

Impaired electrical field induced-stimulation of smooth musclerelaxation in the airway of a mouse model of CF and the administrationof 1-arginine and NO reversed this effect as proposed by M. Mhanna etal. Am. J. Respir. Cell Mol. Biol. 24(5) (200)1 621-626. Graesmann etal., found a positive correlation exists between pulmonary function andexhaled NO and NO metabolite concentrations in the sputum of CF patients(Grasemann, H; Michler, E; Wallot, M; Ratjen, F., Pediatr Pulmonol.1997, 24, 173-7).

Taken together, theses results indicate that increased Arginase activityin CF contributes to the NO deficiency and pulmonary obstruction in CFby limiting the availability of 1-arginine to NOS. Thus, inhibitors ofarginase activity are candidate therapeutics for treating cysticfibrosis (CF)

Organ Protection

Another therapeutic avenue for compounds in accordance with the presentinvention is protecting organs during transport from donor to a sitewhere they will be transplanted into a recipient. Ischemic reperfusioninjury (IR) due to exposure of the transplant organs to a period of warmischemia (time from donor until flushed with preservation media), andcold ischemia (hypothermic preservation) is frequently observed inpatients undergoing transplant surgery. Ischemic reperfusion injury (IR)and accompanying primary graft dysfunction and/or acute or chronicrejection results due to alteration in the cellular activity of theL-Arginine/NO pathway.

It was proposed that Arginase 1 and arginase 2 are released fromapoptotic endothelial cells and kidney cells within the first 24 hoursof organ removal from the body. To counteract the released arginase,L-Arginine is added to preservation media. Results with canine kidneytransplants indicate that addition of L-arginine reduced the incidenceand severity of ischemia, resulted in post-transplant with lower MDAlevels at 1 hour, and lowered BUN & Serum creatinine levels during thefirst 72 hrs. See Erkasap, S; Ates, E., Nephrol Dial Transplant. 2000,15, 1224-7.

Similar results were observed for canine lung grafts over a 24 hourperiod when lungs were preserved in the University of Wisconsin solutionsupplemented with L-Arginine. Yen et al., observed that the addition ofL-arginine to the preservation medium increased pulmonary endothelialprotection and lowered the incidence of ischemia when compared to acontrol that is preserved in medium that does not contain L-arginine(Chu, Y; Wu, Y. C.; Chou, Y. C.; Chueh, H. Y, Liu H P, Chu J J, Lin PJ., J Heart Lung Transplant. 2004, 23, 592-8).

Koch et al. stated that improved myocardial contractility and relaxationin heart muscle of rats following transplantation when hearts werepreserved in HTK solution having L-Arginine and N-alpha-acetyl-histidine(Koch A, Radovits T, Loganathan S, Sack F U, Karck M, Szabó G B.,Transplant Proc. 2009, 41, 2592-4).

Addition of an arginase inhibitor, therefore, can be a candidatetherapeutic for preventing and/or reducing the incidence and risk ofischemic reperfusion injury by a synergistically increasing the organprotective effect of the preservation media. Given the low number ofavailable organs that are suitable for transplant and the loss andinjury of organs due to the onset of ischemia, arginase inhibitors inaccordance with the present invention can find use as therapeutics forpreserving organs, increasing organ availability by reducing the amountof ischemic reperfusion injury during organ transport.

Leishmaniasis

Leishmaniasis is caused by a protozoan and manifests as cutaneousleishmaniasis (i.e., skin infection causing hypo-pigmented nodules) andvisceral lieshmaniasis (more severe affecting internal organs). Arginaseit postulated to play a role in disease progression since the parasiterelies on arginase for the synthesis of cellular polyamines that areessential for pathogenesis Inhibition of arginase, therefore, wouldreduce cellular parasitic burden and promote increased nitric oxide (NO)levels enhancing parasitic clearance. See Liew F Y et al. Eur J Immunol21 (1991) 2489, Iniesta V et al. Parasite Immunol. 24 (2002) 113-118,and Kane M M et al. J. Immunol. 166 (2001) 1141-1147. Compoundsaccording to Formula I or Formula II, therefore can be used astherapeutics for treating liesmaniasis.

Myeloid Derived Suppressor Cells (MDSC)

MDSC's are potent immune modulators that limit immune responses throughseveral pathways, such as, L-arginine depletion via arginase 1 releaseinto the microenvironment (Rodriguez 2009 Cancer Res), MHC restrictedsuppression (Nagaraj S, Gupta K, Pisarev V, Kinarsky L, Sherman S, KangL, Herber D L, Schneck J, Gabrilovich D I., Nat. Med. 2007, 13, 828-35),induction of T regulatory cells (Serafini P, Mgebroff S, Noonan K,Borrello I., Cancer Res. 2008, 68, 5439-49), and production of IL10(Rodrigues J C, Gonzalez G C, Zhang L, Ibrahim G, Kelly J J, Gustafson MP, Lin Y, Dietz A B, Forsyth P A, Yong V W, Parney I F., Neuro Oncol.2010, 12, 351-65) (Sinha P, Clements V K, Bunt S K, Albelda S M,Ostrand-Rosenberg S., J. Immunol. 2007, 179, 977-83), for instance.

It is postulated that tumor development is accompanied by an increase inthe number of MDSC's both peripherally and infiltrated within tumors.See Almand B, Clark J I, Nikitina E, van Beynen J, English N R, Knight SC, Carbone D P, Gabrilovich D I., J Immunol. 2001, 166, 678-89 andGabrilovich D., Nat Rev Immunol. 2004, 4, 941-52. Treatment of tumorbearing mice with established chemotherapeutics such as gemcitabine and5-Fluorouracil eliminates MDSC immunesuppression and results in delayedtumor growth. See Le H K, Graham L, Cha E, Morales J K, Manjili M H,Bear H D., Int Immunopharmacol. 2009, 9, 900-9 and Vincent J, Mignot G,Chalmin F, Ladoire S, Bruchard M, Chevriaux A, Martin F, Apetoh L, RébéC, Ghiringhelli F., Cancer Res. 2010, 70, 3052-61, respectively.Moreover, inhibition of arginase 1 enhanced antitumor immunity byreducing MDSC function. Thus, inhibitors of arginase, such as compoundsin accordance with the present invention reduce or delay tumor growthand can be used in combination with established anti-cancer agents inthe treatment of cancer.

Helicobacter pylori (H. pylori)

Helicobacter pylori (H. pylori) is a Gram-negative bacterium thatcolonizes the human gastric mucosa. Bacterial colonization can lead toacute or chronic gastritis and is highly associated with peptic ulcerdisease and stomach cancer. The observation that the addition ofL-arginine to co-culture of H. pylori and macrophages increased nitricoxide (NO) mediated killing of the H. pylori (Chaturvedi R, Asim M,Lewis N D, Algood H M, Cover T L, Kim P Y, Wilson K T., Infect Immun.2007, 75, 4305-15), supports the hypothesis that bacterial arginasecompetes with macrophage arginase for free arginine that is required fornitric oxide (NO) synthesis. See Gobert A P, McGee D J, Akhtar M, MendzG L, Newton J C, Cheng Y, Mobley H L, Wilson K T., Proc Natl Acad SciUSA. 2001, 98, 13844-9. L-arginine is required for T-cell activation andfor the rapid clearance of bacteria from infected cells. By depletingthe pools of free L-arginine in vivo, H. pyroli reduces arginine-inducedCD3zeta expression on T-cells and prevents T-cell activation andproliferation. See Zabaleta J, McGee D J, Zea A H, Hernandez C P,Rodriguez P C, Sierra R A, Correa P, Ochoa A C., J Immunol. 2004, 173,586-93.

The inhibition of bacterial arginase using the known inhibitor NOHA,however, reestablished CD3 expression on T-cells and (Zabaleta J 2004),and enhanced production of NO by macrophages, thus, promoting macrophagemediated clearance of bacteria from infected cells. See Chaturvedi R,Asim M, Lewis N D, Algood H M, Cover T L, Kim P Y, Wilson K T., InfectImmun. 2007, 75, 4305-15.

Furthermore, Lewis et al., have suggested a role for arginase II in H.pyroli infection. For example, these authors indicate that argII−/−primary macrophages incubated with H. pylori extracts showed enhanced NOproduction and correspondingly an increased (˜15%) NO-mediated killingof bacterial cells (Lewis N D, Asim M, Barry D P, Singh K, de Sablet T,Boucher J L, Gobert A P, Chaturvedi R, Wilson K T., J Immunol. 2010,184, 2572-82) Inhibitors of arginase activity, therefore, may becandidate therapeutics for treating vascular pathophysiology. Inhibitorsof arginase activity, therefore, may be candidate therapeutics fortreating H. pyroli infections and for treating gastric ulcers, pepticulcers and cancer.

Sickle Cell Disease (SCD)

Sickle-cell disease (SCD), or sickle-cell anaemia, or drepanocytosis, isa genetic blood disorder, characterized by red blood cells that assumean abnormal, rigid, sickle shape. Sickling decreases the cells'flexibility and increases the risk of complications. An increase in theconcentration of reactive oxygen species (ROS) in circulation causesadherence of blood cells and consumption of NO that results in poorvasodilation or the inability of blood vessels to vasodilate. Theinability to vasodilate along with the increased adherence of bloodcells in SCD results in vaso occlusive crisis and pain.

Low levels of plasma L-arginine are normally detected in patients withSCD (Morris C R, Kato G J, Poljakovic M, Wang X, Blackwelder W C,Sachdev V, Hazen S L, Vichinsky E P, Morris S M Jr, Gladwin M T., JAMA.2005, 294, 81-90) According to these authors, lysis of red blood cells(RBC's) in patients suffering from SCD causes the release of arginaseand a subsequent lowering of physiological L-Arginine levels. Thissequence of biological events lowers physiological concentrations ofnitric oxide (NO), a signaling molecule that plays a role invasodilation. Other biological events also limit NO bioavailabilty.These include, for example, the uncoupling of nitric oxide synthase(NOS), and the subsequent decrease in physiological NO levels, as wellas the reaction of superoxide (O⁻²) reactive oxygen species with NO tosequester the latter as ONOO⁻.

Based on theses observations, inhibitors of arginase, especiallyarginase I inhibitors are being proposed by the present inventors ascandidate therapeutics for patients with sickle cell disease. As statedabove, SCD causes the uncoupling of eNOS due to low physiological levelsL-arginine Inhibition of arginase present in the blood circulation,however, may address this problem by increasing the physiological levelsL-arginine, the substrate of endothelial nitric oxide synthase (eNOS).This sequence of events, importantly, are proposed by the presentinventors to enhance endothelial function and relieve vasoconstrictionassociated with SCD.

Human Immunodeficiency Virus (HIV)

HIV is caused by virus that infects CD4+ helper T cells and causessevere lymphopaenia that predisposes the infected individuals toopportunistic infection. Although, anti-retroviral therapy (ART) isextensively used to combat HIV infection, the wide spread use ofanti-retroviral drugs has resulted in the generation of resistantstrains of HIV.

A correlation exists between the activity of arginase in patientssuffering from HIV and the severity of HIV disease. That is increasedarginase activity has been correlated to increased viral titres in HIVpatients. These patients also show decrease serum arginine levels aswell as decreased levels of CD4+/CD8+ cells.

Taken together, these observations suggest a role for arginaseinhibitors, such as compounds according to Formulae I or II as candidatetherapeutics in the treatment of HIV infection.

Chronic Hepatitis B Virus (HBV)

Chronic hepatitis B infection is a viral disease that is transmitted bycontact with infected body fluids. Chronic HBV infections arecharacterized by inflammation of the liver and jaundice and if leftuntreated can cause cirrhosis of the liver that can progresses to formhepatocellular carcinomas. Anti-viral drugs currently used, however,have low efficacy against chronic HBV infections. Serum and liverhomogenates of patients with chronic HBV infections show reduced levelsof arginine and increased arginase activity. For infected patientsmoreover, the increased arginase activity is correlated to an impairedcytotoxic T-lymphocytes (CTL) response with reduced IL-2 production andCD3z expression.

Replenishing serum arginine to physiologically acceptable levels,however, reconstituted CD3z and IL-2 expression, implicating a role forarginase inhibitors as potential therapeutics in the treatment ofchronic HBV infections.

Routes of Administration and Dosing Regimen

Despite ample evidence associating arginase inhibition with therapies ofvarious diseases and conditions, only a limited number of compounds areknown that are capable of inhibiting arginase activity. The presentinvention therefore provides compounds and their pharmaceuticalcompositions that are useful in treating a subject suffering from such adisease or condition, as more generally set forth above.

The compound or composition of the invention can be formulated asdescribed hereinabove and is suitable for administration in atherapeutically effective amount to the subject in any number of ways.The therapeutically effective amount of a Formula I or Formula IIcompound can depend upon the amounts and types of excipients used, theamounts and specific types of active ingredients in a dosage form, andthe route by which the compound is to be administered to patients.However, typical dosage forms of the invention comprise a compound, or apharmaceutically acceptable salt, solvate, hydrate, isomer, or prodrugthereof.

Typical dosage levels for Formula I or Formula II compounds generallyrange from about 0.001 to about 100 mg per kg of the patient's bodyweight per day which can be administered in single or multiple doses. Anexemplary dosage is about 0.01 to about 25 mg/kg per day or about 0.05to about 10 mg/kg per day. In other embodiments, the dosage level isfrom about 0.01 to about 25 mg/kg per day, about 0.05 to about 10 mg/kgper day, or about 0.1 to about 5 mg/kg per day.

A dose typically ranges from about 0.1 mg to about 2000 mg per day,given as a single once-a-day dose or, alternatively, as divided dosesthroughout the day, optionally taken with food. In one embodiment, thedaily dose is administered twice daily in equally divided doses. A dailydose range can be from about 5 mg to about 500 mg per day, such as, forexample, between about 10 mg and about 300 mg per day. In managing thepatient, the therapy can be initiated at a lower dose, perhaps fromabout 1 mg to about 25 mg, and increased if necessary up to from about200 mg to about 2000 mg per day as either a single dose or divideddoses, depending on the patient's global response.

Depending on the disease to be treated and the subject's condition, thecompounds according to Formula I or Formula II may be administered byoral, parenteral (e.g., intramuscular, intraperitoneal, intravenous,ICV, intracisternal injection or infusion, subcutaneous injection orimplant), inhalation, nasal, vaginal, rectal, sublingual, or topical(e.g., transdermal, local) routes of administration. The compounds canbe formulated, alone or together, in suitable dosage unit formulationscontaining conventional non-toxic pharmaceutically acceptable carriers,adjuvants and vehicles, as described above, that are appropriate foreach route of administration. The invention also contemplatesadministration of the compounds of the invention in a depot formulation,in which the active ingredient is released over a defined time period.

Inhibition of Arginase

The inventive compounds inhibit human arginase I (ARG I) and arginase II(ARG II) as evidenced by an ex vivo assay set forth by a publishedprotocol (Baggio et al. J. Pharmacol. Exp. Ther. 1999, 290, 1409-1416).The assay established the concentration of inhibitor that is required toreduce arginase activity by 50% (IC₅₀).

Assay Protocol

Inhibition of arginase I (ARG I) and arginase II (ARG II) by Formula Iand Formula II compounds is followed spectrophotometrically at 530 nm.The compound to be tested is dissolved in DMSO at an initialconcentration 50-fold greater than its final concentration in thecuvette. 10 μl of the stock solution is diluted in 90 μl of the assaybuffer that comprises 0.1M sodium phosphate buffer containing 130 mMNaCl, pH 7.4, to which is added ovalbumin (OVA) at a concentration of 1mg/ml. Solutions of arginase I and II are prepared in 100 mM sodiumphosphate buffer, pH 7.4 containing 1 mg/ml of OVA to give an arginasestock solution at a final concentration of 100 ng/ml.

To each well of a 96-well microtiter plate is add 40 μl of enzyme, 10 μlof an inventive compound and 10 μl of enzyme substrate(L-arginine+manganese sulfate). For wells that are used as positivecontrols, only the enzyme and its substrate are added, while wells usedas negative controls contain only manganese sulfate.

After incubating the microtiter plate at 37° C. for 60 minutes, 150 μlof a urea reagent obtained by combining equal proportions (1:1) ofreagents A and B is added to each well of the microtiter plate to stopthe reaction. The urea reagent is made just before use by combiningReagent A (10 mM o-phthaldialdehyde, and 0.4% polyoxyethylene (23)lauryl ether (w/v) in 1.8 M sulfuric acid) with Reagent B (1.3 mMprimaquine diphosphate, 0.4% polyoxyethylene (23) lauryl ether (w/v),130 mM boric acid in 3.6 M sulfuric acid). After quenching the reactionmixture, the microtiter plate is allowed to stand for an additional 10minutes at room temperature to allow color development. The inhibitionof arginase is computed by measuring the optical density (OD) of thereaction mixture at 530 nm and normalizing the OD value to percentinhibition observed in the control. The normalized OD is then used togenerate a dose-response curve by plotting the normalized OD valuesagainst log [concentration] and using regression analysis to compute theIC₅₀ values.

Table 2 below ranks the potency of Formula I compounds on a scale from 1through 5, that is, the most potent compounds are designated as 1 andthe least potent compounds being designated as 5. A similar potencyanalysis for Formula II compounds is illustrated in Table 2-A. Thus, apotency value of 1 refers to inventive compounds with IC₅₀ values in therange from 0.1 nM to 250 nM; a potency value of 2 refers to inventivecompounds with IC₅₀ values in the range from 251 nM to 1000 nM;compounds having a potency value of 3 exhibit IC₅₀ values in the rangefrom 1001 nM to 2000 nM; inventive compounds with IC₅₀ values in therange from 2001 nM to 5000 nM are assigned a potency value of 4, andcompounds with IC₅₀ values above 5001 nM are assigned a potency value of5.

TABLE 2 Potency Potency Ex. # Structure (ARG I)^(a) (ARG II)^(a) 1

 2 2 2

 2 2 3

 3 3 4

 2 2 5

 3 4 6

 2 3 7

 1 2 8

 3 4 9

 1 2 10

 1 2 11

 1 1 12

 1 1 13

 1 2 14

43 5 15

 4 4 16

 2 3 17

 4 4 18

 4 4 19

 4 3 20

 4 4 21

 3 3 22

 2 2 23

 2 2 24

— 4 25

 2 2 26

 2 2 27

 3 3 28

 2 3 29

 2 3 30

 2 3 31

 2 2 32

— 4 33

 2 2 34

 2 3 35

4 36

 2 3 37

 2 3 38

 4 4 39

 3 4 40

 3 4 41

 3 4 42

 4 4 43

 3 4 44

 5 5 45

 3 4 46

 5 5 47

 3 4 48

 4 5 49

 4 4 50

 5 5 51

 3 4 52

 4 4 53

 4 4 54

 5 5 55

 1 2 56

 3 4 57

 3 3 58

 1 1 59

 3 4 60

 1 2 61

 2 3 62

 2 3 63

 1 1 64

 1 1 65

 1 1 66

 1 1 67

 2 2 68

 2 2 69

 1 1 70

 1 2 71

 4 4 72

 2 2 73

 1 2 74

 4 5 75

 2 3 76

 5 5 77

 4 5 78

 4 4 79

 4 5 80

 4 5 81

— 5 82

— 4 83

 4 4 84

 4 5 85

 4 4 86

 4 4 87

 3 3 88

 4 3 89

 5 5 90

 4 4 91

 4 4 92

 5 5 93

 5 5 94

 5 5 95

 4 4 96

 3 3 97

 4 5 98

— 5 99

— 5 100

— 5 101

 4 — 102

 4 4 103

— 5 104

— 5 105

— 5 106

 5 5 107

 5 5 108

 3 4 109

 4 5 110

 3 4 111

 4 4 112

 4 4 113

 1 2 114

 5 5 115

 1 1 116

 4 4 117

 2 4 118

 2 2 119

 2 3 120

 3 4 121

 2 2 122

 2 2 123

 4 5 124

 2 4 125

 2 2 126

 2 2 127

 2 2 128

 2 3 129

 2 3 130

 1 2 131

 2 — 132

 1 2 133

 1 1 134

 1 2 135

 1 2 136

 1 1 137

 1 1 138

 1 1 139

 1 1 140

 1 1 141

 1 1 142

 2 2 143

 1 1 144

 1 1 145

 3 3 146

 3 4 147

 1 2 148

 1 1 149

 1 1 ^(a)Order of Potency (highest-lowest): 1 = 0.1 nM → 250 nM; 2 = 251nM → 1000 nM; 3 = 1001 nM → 2000 nM; 4 = 2001 nM → 5000 nM; and 5 = 5001nM → greater.

Table 2-A below ranks the inhibition potency of exemplary Formula IIcompounds for arginase I (ARG I) and arginase II (ARG II).

TABLE 2-A Potency Potency Ex # Structure (ARG I)^(a) (ARG)^(a) 1-A

2 3 2-A

3 4 3-A

3 3 4-A

2 3 5-A

3 2 6-A

2 3 7-A

3 4 8-A

4 4 9-A

3 4 10-A

4 4 11-A

2 2 12-A

4 4 13-A

4 4 14-A

4 4 15-A

1 1 16-A

1 1 17-A

1 1 18-A

4 4 19-A

4 4 20-A

2 2 21-A

2 3 22-A

2 2 23-A

2 2 24-A

2 2 25-A

1 2 26-A

4 4 27-A

4 4 28-A

4 4 29-A

3 5 30-A

4 4 31-A

3 4 32-A

2 2 33-A

3 3 34-A

2 2 35-A

2 2 36-A

2 4 37-A

2 3 38-A

2 2 39-A

2 2 40-A

2 2 41-A

2 1 42-A

2 3 43-A

2 3 44-A

2 3 45-A

2 3 46-A

1 1 47-A

1 2 48-A

1 2 49-A

2 1 50-A

1 2 51-A

1 2 52-A

1 1 53-A

2 2 54-A

1 2 55-A

1 1 56-A

1 2 57-A

1 2 58-A

1 2 59-A

1 1 60-A

1 1 61-A

1 1 62-A

2 2 63-A

1 1 64-A

1 1 65-A

1 1 66-A

1 1 67-A

2 2 68-A

2 2 69-A

2 3 70-A

— — 71-A

72-A

1 2 73-A

1 2 74-A

1 1 75-A

1 2 76-A

1 1 77-A

1 1 78-A

1 1 79-A

1 1 80-A

1 1 81-A

1 1 82-A

1 1 83-A

1 1 84-A

5 5 85-A

3 2 86-A

5 5 87-A

1 1 88-A

2 2 89-A

1 1 90-A

1 1 91-A

1 2 92-A

1 1 93-A

2 2 94-A

1 2 95-A

1 2 96-A

1 2 97-A

2 2 98-A

1 1 99-A

1 1 100-A

1 1 101-A

2 1 102-A

1 1 103-A

1 1 104-A

1 1 105-A

2 2 106-A

2 2 ^(a)Order of Potency: 1 = 0.1 nM-250 nM; 2 = 251 nM-1000 nM; 3 =1001 nM-2000 nM; 4 = 2001 nM-5000 nM; and 5 = 5001 nM or greater.

Efficacy Model

As described hereinabove, the compounds according to the invention areuseful in the treatment and prevention of a variety of disorders andconditions that are affected by levels of nitric oxide (NO) regulated,in part, by arginase enzymes. The compounds are assessed for efficacy insuch treatment and prevention by their performances in standardized invivo tests. In vivo models to assess efficacy are developed for thispurpose as described below.

Erectile Dysfunction (ED)

The inventive compounds are candidate therapeutics for treating ED, asassessed by measurements of penile erectile response according to aprotocol described by Wingard C, Fulton J, and Husain S, J Sex Med 4:348-363, 2007. Table 3 below presents the erectile responses:

TABLE 3 Treatment Structure Effect* Baseline — — 0.9% NaCl — 0 Ex. 13

+++ Enantiomer of Ex. 13

0 *increased response relative to baseline @ 2.5 V stimulation; 0<10%; + 11-50%; ++ 51-100%; +++ >100%

This example demonstrates that Example 13 is effective in elicitingerectile responses in vivo, whereas the enantiomer of Example 13 is not.

The foregoing examples are intended illustrate certain embodiments ofthe invention, which is defined in full below by the claims. Inaddition, all publications cited herein are incorporated by reference asif fully set forth herein.

We claim:
 1. A compound according to Formula II,

wherein R⁶ is —OH; R⁷ is H; X is (C₃-C₁₄)-cycloalkylene; Y is —NR′R″; Mis selected from a bond, —(C₁-C₆)alkylene-, —O—, —C(O)—, —C(S)—,—C(O)NH—, —C(S)NH—, —S—, —S(O)—, —S(O)₂—, and —NR′—; R⁸ and R⁹ are eachhydrogen, D is butylene; R′ and R″ are independently selected from H,(C₁-C₈)alkyl, —C(O)—(C₁-C₈)alkylene, optionally substituted (C₃-C₆)aryl,optionally substituted (C₃-C₁₄)aryl(C₁-C₆)alkylene-, optionallysubstituted (C₁-C₆)aminoalkyl, optionally substituted (C₃-C₆)cycloalkyl,optionally substituted (C₃-C₁₄)heterocycloalkyl, optionally substituted(C₃-C₁₄)heteroaryl; and wherein any alkyl, alkylene, aryl, heteroaryl,cycloalkyl, or heterocycloalkyl is optionally substituted with one ormore members selected from halogen, oxo, —COOH, —CN, —NO₂, —OH,—NR^(d)R^(e), —NR^(g)S(O)₂R^(h), (C₁-C₆)alkyl, (C₁-C₆)haloalkyl,(C₁-C₆)haloalkoxy, (C₁-C₆)alkoxy, (C₃-C₁₄)aryl, (C₃-C₁₄)heteroaryl,(C₃-C₁₄)heterocycloalkyl, (C₃-C₁₄)heteroaryl-(C₁-C₆)alkylene and(C₃-C₁₄)aryloxy; wherein R^(d), R^(e), R^(g), and R^(h) are eachindependently selected from H, straight or branched (C₁-C₆)alkyl,optionally substituted (C₃-C₁₄)aryl(C₁-C₆)alkylene-, optionallysubstituted (C₃-C₁₄)aryl, (C₁-C₆)hydroxyalkyl, (C₁-C₆)aminoalkyl,H₂N(C₁-C₆)alkylene-, optionally substituted (C₃-C₆)cycloalkyl,optionally substituted (C₃-C₁₄)heterocycloalkyl, optionally substituted(C₃-C₁₄)heteroaryl, optionally substituted(C₃-C₁₄)aryl-(C₁-C₆)alkylene-, and NR′R″C(O)—, or a pharmaceuticallyacceptable salt, stereoisomer, tautomer, or prodrug thereof.
 2. Thecompound according to claim 1, wherein M is a bond and Y is —NH₂.
 3. Thecompound according to claim 1 that is selected from the following table:

or a pharmaceutically acceptable salt thereof.
 4. The compound accordingto claim 3 that is selected from:

or a pharmaceutically acceptable salt thereof.
 5. A pharmaceuticalcomposition comprising at least one compound according to claim 1, or apharmaceutically acceptable salt, stereoisomer, tautomer, or prodrugthereof; and a pharmaceutically acceptable carrier.
 6. The compoundaccording to claim 1, wherein Y is —NHR′.
 7. The compound according toclaim 6, R′ is optionally substituted (C₃-C₁₄)aryl(C₁-C₆)alkylene-. 8.The compound according to claim 6, R′ is (C₁-C₈)alkyl.